Index: maven-artifact/src/main/java/org/apache/maven/artifact/DefaultArtifact.java
===================================================================
--- maven-artifact/src/main/java/org/apache/maven/artifact/DefaultArtifact.java	(revision 510454)
+++ maven-artifact/src/main/java/org/apache/maven/artifact/DefaultArtifact.java	(working copy)
@@ -86,6 +86,8 @@
     private Map metadataMap;
 
     private boolean optional;
+    
+    private String modelRepresentation;
 
     public DefaultArtifact( String groupId, String artifactId, VersionRange versionRange, String scope, String type,
                             String classifier, ArtifactHandler artifactHandler )
@@ -584,4 +586,14 @@
     {
         this.optional = optional;
     }
+
+    public String getModelRepresentation()
+    {
+        return modelRepresentation;
+    }
+
+    public void setModelRepresentation( String modelRepresentation )
+    {
+        this.modelRepresentation = modelRepresentation; 
+    }
 }
Index: maven-artifact/src/main/java/org/apache/maven/artifact/Artifact.java
===================================================================
--- maven-artifact/src/main/java/org/apache/maven/artifact/Artifact.java	(revision 510454)
+++ maven-artifact/src/main/java/org/apache/maven/artifact/Artifact.java	(working copy)
@@ -167,4 +167,9 @@
 
     boolean isSelectedVersionKnown()
         throws OverConstrainedVersionException;
+
+    // For MNG-624, we sometimes need a slightly modified model to install and deploy
+    String getModelRepresentation();
+
+    void setModelRepresentation( String modelRepresentation );
 }
\ No newline at end of file
Index: maven-artifact-manager/src/main/java/org/apache/maven/artifact/deployer/DefaultArtifactDeployer.java
===================================================================
--- maven-artifact-manager/src/main/java/org/apache/maven/artifact/deployer/DefaultArtifactDeployer.java	(revision 510454)
+++ maven-artifact-manager/src/main/java/org/apache/maven/artifact/deployer/DefaultArtifactDeployer.java	(working copy)
@@ -68,16 +68,30 @@
 
         try
         {
+            // This updates the artifact and causes the artifactFile (below) location computation to likely change (especially for snapshots)
             transformationManager.transformForDeployment( artifact, deploymentRepository, localRepository );
 
-            // Copy the original file to the new one if it was transformed
+            // A location in the local repository to stash our artifact before uploading
             File artifactFile = new File( localRepository.getBasedir(), localRepository.pathOf( artifact ) );
-            if ( !artifactFile.equals( source ) )
+
+            if ( "pom".equals( artifact.getType() ) && artifact.getModelRepresentation() != null )
             {
-                FileUtils.copyFile( source, artifactFile );
+                // MNG-624: Need to use our expanded model that includes the proper <parent/> entries
+                FileUtils.fileWrite( artifactFile.getAbsolutePath(), artifact.getModelRepresentation() );
+                
+                // Need to put the artifactFile we just wrote, not the source
+                // Note: The source for a pom is the file you edit, don't want to change it!
+                wagonManager.putArtifact( artifactFile, artifact, deploymentRepository );
             }
+            else
+            {
+                if ( !artifactFile.equals( source ) )
+                {
+                    FileUtils.copyFile( source, artifactFile );
+                }
 
-            wagonManager.putArtifact( source, artifact, deploymentRepository );
+                wagonManager.putArtifact( source, artifact, deploymentRepository );
+            }
 
             // must be after the artifact is installed
             for ( Iterator i = artifact.getMetadataList().iterator(); i.hasNext(); )
Index: maven-artifact-manager/src/main/java/org/apache/maven/artifact/installer/DefaultArtifactInstaller.java
===================================================================
--- maven-artifact-manager/src/main/java/org/apache/maven/artifact/installer/DefaultArtifactInstaller.java	(revision 510454)
+++ maven-artifact-manager/src/main/java/org/apache/maven/artifact/installer/DefaultArtifactInstaller.java	(working copy)
@@ -68,10 +68,20 @@
                 destination.getParentFile().mkdirs();
             }
 
-            getLogger().info( "Installing " + source.getPath() + " to " + destination );
+            if ( "pom".equals( artifact.getType() ) && artifact.getModelRepresentation() != null )
+            {
+                getLogger().info( "Installing expanded " + source.getPath() + " to " + destination );
 
-            FileUtils.copyFile( source, destination );
+                // For MNG-624, we cannot always just copy the pom if part of the <parent/> was inferred and computed
+                FileUtils.fileWrite( destination.getAbsolutePath(), artifact.getModelRepresentation() );
+            }
+            else
+            {
+                getLogger().info( "Installing " + source.getPath() + " to " + destination );
 
+                FileUtils.copyFile( source, destination );
+            }
+
             // must be after the artifact is installed
             for ( Iterator i = artifact.getMetadataList().iterator(); i.hasNext(); )
             {
Index: maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java
===================================================================
--- maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java	(revision 510454)
+++ maven-project/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java	(working copy)
@@ -47,6 +47,7 @@
 import org.apache.maven.model.ReportPlugin;
 import org.apache.maven.model.Repository;
 import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
+import org.apache.maven.model.io.xpp3.MavenXpp3Writer;
 import org.apache.maven.profiles.DefaultProfileManager;
 import org.apache.maven.profiles.MavenProfilesBuilder;
 import org.apache.maven.profiles.ProfileManager;
@@ -115,6 +116,7 @@
 
  * inheritance
  * interpolation
+ * validate inheritance (so variables and missing elements can be applied to <parent>)
  * defaults injection
  * path translation
 
@@ -131,6 +133,14 @@
 */
 
 /**
+ * Read in a model (pom.xml) from disk, local or remote repository and build a project from it.
+ * 
+ * In the process of processing the model, parent-models will be found and relevant things extracted:
+ * variables, profiles, plugins, dependencies.
+ * 
+ * Sub-modules are processed by L{org.apache.maven.DefaultMaven} which is generally what calls into
+ * this class regardless.
+ * 
  * @version $Id: DefaultMavenProjectBuilder.java,v 1.37 2005/03/08 01:55:22
  *          trygvis Exp $
  */
@@ -280,7 +290,8 @@
 
         try
         {
-            project = processProjectLogic( "<Super-POM>", project, null, null, true );
+            project = expandProjectDefinition( project, null, null, true );
+            processProjectLogic( "<Super-POM>", project );
 
             project.setExecutionRoot( true );
 
@@ -709,19 +720,20 @@
         }
 
         project.setOriginalModel( originalModel );
-        
-        rawProjectCache.put( createCacheKey( project.getGroupId(), project.getArtifactId(), project.getVersion() ), new MavenProject( project ) );
 
+        MavenProject rawProject = new MavenProject( project ); // Non-interpolated read-only wo/parent
+ 
         // we don't have to force the collision exception for superModel here, it's already been done in getSuperModel()
         MavenProject previousProject = superProject;
 
-        Model previous = superProject.getModel();
+        Model previous = superProject.getModel(); // parent
 
+        // Using information from a project's lineage, fix any missing attributes in models (modifying them)
         for ( Iterator i = lineage.iterator(); i.hasNext(); )
         {
             MavenProject currentProject = (MavenProject) i.next();
 
-            Model current = currentProject.getModel();
+            Model current = currentProject.getModel(); // child
 
             String pathAdjustment = null;
 
@@ -757,19 +769,66 @@
 
         try
         {
-            project = processProjectLogic( pomLocation, project, externalProfileManager, projectDir, strict );
+            project = expandProjectDefinition( project, externalProfileManager, projectDir, strict );
+            
+            // Fixup/validate parent if we had any variables in the version strings initially
+            validateImpliedInheritance( project, pomLocation, externalProfileManager, strict );
+            
+            if ( originalModel.getParent() != null && !isParentIdExpanded( originalModel.getParent() ) )
+            {
+                // If we had to fix the implied inheritance and in the process patch our version or group, we may need
+                // to expand again to ensure any thing like ${pom.version} in dependencies, etc. is properly expanded
+                project = expandProjectDefinition( project, externalProfileManager, projectDir, strict );
+            }
         }
         catch ( ModelInterpolationException e )
         {
             throw new InvalidProjectModelException( projectId, pomLocation, e.getMessage(), e );
         }
+
+        // Finish processing the project logic...
+        try
+        {
+            processProjectLogic( pomLocation, project );
+        }
         catch ( InvalidRepositoryException e )
         {
             throw new InvalidProjectModelException( projectId, pomLocation, e.getMessage(), e );
         }
 
-        processedProjectCache.put( createCacheKey( project.getGroupId(), project.getArtifactId(), project.getVersion() ), project );
+        
+        if ( ( originalModel.getParent() != null && !isParentIdExpanded( originalModel.getParent() ) ) ) // || !isModelIdExpanded( originalModel ) )
+        {
+            // Write a modified data segment to the artifact
+            Model newModel = ModelUtils.cloneModel( originalModel );
+            newModel.setParent( project.getModel().getParent() );
+            newModel.setGroupId( project.getGroupId() );
+            newModel.setVersion( project.getVersion() );
+            
+            StringWriter sWriter = new StringWriter();
 
+            MavenXpp3Writer writer = new MavenXpp3Writer();
+            try
+            {
+                writer.write( sWriter, newModel );
+            }
+            catch ( IOException e )
+            {
+                throw new ProjectBuildingException( projectId, "Cannot serialize modified model", e );
+            }
+            
+            sWriter.write( "\n<!-- Updated pom.xml to include implied or expanded parent, group and version tags during build -->\n" );
+            
+            getLogger().debug( "New model:\n" + sWriter.toString() );
+            
+            project.getArtifact().setModelRepresentation( sWriter.toString() );
+        }
+        
+        String cacheKey = createCacheKey( project.getGroupId(), project.getArtifactId(), project.getVersion() );
+        
+        rawProjectCache.put( cacheKey, rawProject ); // do it here after version's been expanded
+        processedProjectCache.put( cacheKey, project );
+        
         // jvz:note
         // this only happens if we are building from a source file
         if ( projectDescriptor != null )
@@ -793,7 +852,7 @@
         
         if ( rawParent != null )
         {
-            String cacheKey = createCacheKey( rawParent.getGroupId(), rawParent.getArtifactId(), rawParent.getVersion() );
+            cacheKey = createCacheKey( rawParent.getGroupId(), rawParent.getArtifactId(), rawParent.getVersion() );
             
             MavenProject processedParent = (MavenProject) processedProjectCache.get( cacheKey );
             
@@ -806,7 +865,115 @@
 
         return project;
     }
+
+    /**
+     * If the project's parent definition or its actual parent had any variables in their definition or any missing
+     * details, assembleLineage() would have had to guess at who our parent was. This routine verifies who our parent 
+     * really is and makes sure that missing details are filled-in and any variables are suitably expanded.
+     */
+    private void validateImpliedInheritance(MavenProject project, String pomLocation, ProfileManager externalProfileManager, boolean strict) 
+        throws ProjectBuildingException, InvalidProjectModelException
+    {
+        Parent projectModelParent = project.getModel().getParent();
+        MavenProject candidateParentProject = project.getParent();
     
+        if ( projectModelParent != null && candidateParentProject != null && candidateParentProject.getModel() != null )
+        {
+            Model candidateParentModel = candidateParentProject.getOriginalModel();
+            if ( candidateParentModel == null )
+            {
+                candidateParentModel = project.getParent().getModel();
+            }
+                      
+            Parent originalProjectModelParent = null;
+            if ( project.getOriginalModel() != null )
+            {
+                originalProjectModelParent = project.getOriginalModel().getParent();
+            }
+          
+            String version = fixParentVersion( project );
+            String groupId = fixParentGroupId( project );
+            fixParentArtifactId( project );
+            
+            if ( originalProjectModelParent != null && ( !isParentIdExpanded( originalProjectModelParent ) || !isModelIdExpanded( candidateParentModel ) ) )
+            {
+                // Now that our model has been expanded (interpolated + profiles injected, etc.), parent-version will be expanded
+                String parentKey = createCacheKey( projectModelParent.getGroupId(), projectModelParent.getArtifactId(), projectModelParent.getVersion() );
+
+                // Try to get the processed (interpolated, etc.) parent
+                MavenProject parentProject = (MavenProject) processedProjectCache.get( parentKey );
+
+                if ( parentProject != null )
+                {
+                    // We have the parent, we just weren't able to match it before, but now we can
+                    project.setParent( new MavenProject( parentProject ) ); // expanded read-only wo/parent
+
+                    if ( getLogger().isDebugEnabled() )
+                    {
+                        getLogger().debug( "Found " + project.getId() + "'s parent: " + parentProject.getId() );
+                    }
+                }
+                else
+                {
+                    // We're probably running mvn below the parent, so we've probably just read the parent pom.xml in when building lineage
+                    // Thus, we need to expand/interpolate the parent so we can properly compare versions to ensure they match
+                    try 
+                    {
+                        candidateParentProject = project.getParent(); // non-expanded
+                        candidateParentProject = expandProjectDefinition( candidateParentProject, externalProfileManager, candidateParentProject.getFile(), strict );
+                        boolean reExpand = false;
+                        
+                        // It is quite possible that the candidate tried to inherit its version too...
+                        if ( StringUtils.isEmpty( candidateParentProject.getVersion() ) )
+                        {
+                            candidateParentProject.setVersion( version );
+                            reExpand = true;
+                        }
+                        
+                        if ( StringUtils.isEmpty( candidateParentProject.getGroupId() ) )
+                        {
+                            candidateParentProject.setGroupId( groupId );
+                            reExpand = true;
+                        }
+                        
+                        if ( reExpand )
+                        {
+                            candidateParentProject = expandProjectDefinition( candidateParentProject, externalProfileManager, candidateParentProject.getFile(), strict );
+                        }
+                    }
+                    catch ( ModelInterpolationException e )
+                    {
+                        throw new ProjectBuildingException( project.getId(), "Unable to expand " + project.getId() + "'s pom.xml.", e );
+                    }
+
+                    // Now validate that everything matches
+                    if ( !projectModelParent.getGroupId().equals( candidateParentProject.getGroupId() ) ||
+                         !projectModelParent.getArtifactId().equals( candidateParentProject.getArtifactId() ) ||
+                         !projectModelParent.getVersion().equals( candidateParentProject.getVersion() ) ) 
+                    {
+                        throw new ProjectBuildingException( project.getId(), "Unable to find parent for " + project.getId() +
+                                                                             "\n Specified: " + projectModelParent.getId() +
+                                                                             "\n Found:     " + candidateParentProject.getId() );
+                    }
+
+                    project.setParent( candidateParentProject );
+
+                    if ( getLogger().isDebugEnabled() )
+                    {
+                        getLogger().debug( "Interpolated and matched " + project.getId() + "'s candidate parent: " + candidateParentProject.getId() );
+                    }
+                }
+                
+                if ( project.getGroupId().equals( project.getParent().getGroupId() ) &&
+                     project.getArtifactId().equals( project.getParent().getArtifactId() ) )
+                {
+                    throw new ProjectBuildingException( project.getId(), "Parent groupId/artifactId in '" + pomLocation + 
+                                                                         "' is a duplicate of the current project" );
+                }
+            }
+        }
+    }
+
     private String safeVersionlessKey( String groupId, String artifactId )
     {
         String gid = groupId;
@@ -842,18 +1009,16 @@
     }
 
     /**
-     * @todo can this take in a model instead of a project and still be successful?
-     * @todo In fact, does project REALLY need a MavenProject as a parent? Couldn't it have just a wrapper around a
-     * model that supported parents which were also the wrapper so that inheritence was assembled. We don't really need
-     * the resolved source roots, etc for the parent - that occurs for the parent when it is constructed independently
-     * and projects are not cached or reused
+     * Return a new project based on an interpolated model that's had the active profiles injected.
+     *
+     * @param project    The unexpanded (original) maven project
+     * @param profileMgr The profile manager
+     * @param projectDir The directory for this maven project
+     * @param strict     Should we be strict processing the pom.xml?
+     * @return A new project based on the expanded project/model definition
      */
-    private MavenProject processProjectLogic( String pomLocation,
-                                              MavenProject project,
-                                              ProfileManager profileMgr,
-                                              File projectDir,
-                                              boolean strict )
-        throws ProjectBuildingException, ModelInterpolationException, InvalidRepositoryException
+    private MavenProject expandProjectDefinition( MavenProject project, ProfileManager profileMgr, File projectDir, boolean strict )
+        throws ProjectBuildingException, ModelInterpolationException
     {
         Model model = project.getModel();
 
@@ -904,11 +1069,38 @@
 
         project.setActiveProfiles( activeProfiles );
 
+        project.setParent( parentProject );
+
+        return project;
+    }
+
+    /**
+     * @todo can this take in a model instead of a project and still be successful?
+     * @todo In fact, does project REALLY need a MavenProject as a parent? Couldn't it have just a wrapper around a
+     * model that supported parents which were also the wrapper so that inheritence was assembled. We don't really need
+     * the resolved source roots, etc for the parent - that occurs for the parent when it is constructed independently
+     * and projects are not cached or reused
+     */
+    private void processProjectLogic( String pomLocation, MavenProject project )
+        throws ProjectBuildingException, InvalidRepositoryException
+    {
+        MavenProject parentProject = project.getParent();
+        
         // TODO: maybe not strictly correct, while we should enfore that packaging has a type handler of the same id, we don't
         Artifact projectArtifact = artifactFactory.createBuildArtifact( project.getGroupId(), project.getArtifactId(),
                                                                         project.getVersion(), project.getPackaging() );
         project.setArtifact( projectArtifact );
 
+        if ( parentProject != null )
+        {
+            Artifact parentArtifact = artifactFactory.createParentArtifact( parentProject.getGroupId(),
+                                                                            parentProject.getArtifactId(),
+                                                                            parentProject.getVersion() );
+            project.setParentArtifact( parentArtifact );
+        }
+
+        Model model = project.getModel();
+        
         project.setPluginArtifactRepositories( ProjectUtils.buildArtifactRepositories( model.getPluginRepositories(),
                                                                                        artifactRepositoryFactory,
                                                                                        container ) );
@@ -929,16 +1121,6 @@
             }
         }
 
-        project.setParent( parentProject );
-
-        if ( parentProject != null )
-        {
-            Artifact parentArtifact = artifactFactory.createParentArtifact( parentProject.getGroupId(),
-                                                                            parentProject.getArtifactId(),
-                                                                            parentProject.getVersion() );
-            project.setParentArtifact( parentArtifact );
-        }
-
         // Must validate before artifact construction to make sure dependencies are good
         ModelValidationResult validationResult = validator.validate( model );
 
@@ -959,8 +1141,6 @@
         project.setReportArtifacts( createReportArtifacts( projectId, project.getReportPlugins() ) );
 
         project.setExtensionArtifacts( createExtensionArtifacts( projectId, project.getBuildExtensions() ) );
-
-        return project;
     }
 
     /**
@@ -1026,6 +1206,12 @@
         }
 
         MavenProject project = new MavenProject( model );
+        
+        // If building from the middle of a lineage (i.e. child in a parent-child-grandchild project), child will be found in rawProjectCache,
+        // but without this, its parent may not be found in cache. Thus, location of pom.xml is important. And it can't be a directory as
+        // despite user documentation saying otherwise, there are a number of places in maven where File.getParent() is called assuming it
+        // will retrieve the directory where the pom.xml is stored.
+        project.setFile( new File( projectDir, "pom.xml" ) );
 
         project.setActiveProfiles( activeProfiles );
 
@@ -1037,31 +1223,28 @@
         {
             String projectId = safeVersionlessKey( model.getGroupId(), model.getArtifactId() );
 
-            if ( StringUtils.isEmpty( parentModel.getGroupId() ) )
+            if ( isParentIdExpanded( parentModel ) && isModelIdExpanded( model ) && 
+                 parentModel.getGroupId().equals( model.getGroupId() ) &&
+                 parentModel.getArtifactId().equals( model.getArtifactId() ) )
             {
-                throw new ProjectBuildingException( projectId, "Missing groupId element from parent element" );
+                throw new ProjectBuildingException( projectId, "Parent groupId/artifactId in '" + project.getFile() + 
+                                                               "' is a duplicate of the current project" );
             }
-            else if ( StringUtils.isEmpty( parentModel.getArtifactId() ) )
-            {
-                throw new ProjectBuildingException( projectId, "Missing artifactId element from parent element" );
-            }
-            else if ( parentModel.getGroupId().equals( model.getGroupId() ) &&
-                parentModel.getArtifactId().equals( model.getArtifactId() ) )
-            {
-                throw new ProjectBuildingException( projectId, "Parent element is a duplicate of " + "the current project " );
-            }
-            else if ( StringUtils.isEmpty( parentModel.getVersion() ) )
-            {
-                throw new ProjectBuildingException( projectId, "Missing version element from parent element" );
-            }
 
             // the only way this will have a value is if we find the parent on disk...
             File parentDescriptor = null;
 
             model = null;
             
+            MavenProject parentProject = null;
+            
             String parentKey = createCacheKey( parentModel.getGroupId(), parentModel.getArtifactId(), parentModel.getVersion() );
-            MavenProject parentProject = (MavenProject) rawProjectCache.get( parentKey );
+            
+            // If none of the parent needs to be interpolated, look up in the rawProjectCache
+            if ( isParentIdExpanded( parentModel ) )
+            {
+                parentProject = (MavenProject) rawProjectCache.get( parentKey );
+            }
     
             if ( parentProject != null )
             {
@@ -1121,21 +1304,20 @@
                 {
                     Model candidateParent = readModel( projectId, parentDescriptor, strict );
 
-                    String candidateParentGroupId = candidateParent.getGroupId();
-                    if ( candidateParentGroupId == null && candidateParent.getParent() != null )
+                    if ( !isParentIdExpanded( parentModel ) || !isModelIdExpanded( candidateParent ) )
                     {
-                        candidateParentGroupId = candidateParent.getParent().getGroupId();
+                        // Just use POM we found above us. We'll validate everything later
+                        model = candidateParent;
+                            
+                        if ( getLogger().isDebugEnabled() )
+                        {
+                            getLogger().debug( "Using parent-POM from the project hierarcy for " + 
+                                               project.getId() + " but id must still be validated." );
+                        }
                     }
-
-                    String candidateParentVersion = candidateParent.getVersion();
-                    if ( candidateParentVersion == null && candidateParent.getParent() != null )
-                    {
-                        candidateParentVersion = candidateParent.getParent().getVersion();
-                    }
-
-                    if ( parentModel.getGroupId().equals( candidateParentGroupId ) &&
+                    else if ( parentModel.getGroupId().equals( getModelGroupId( candidateParent ) ) &&
                         parentModel.getArtifactId().equals( candidateParent.getArtifactId() ) &&
-                        parentModel.getVersion().equals( candidateParentVersion ) )
+                        parentModel.getVersion().equals( getModelVersion( candidateParent ) ) )
                     {
                         model = candidateParent;
 
@@ -1160,6 +1342,25 @@
             // only resolve the parent model from the repository system if we didn't find it on disk...
             if ( model == null )
             {
+                if ( !isParentIdExpanded( parentModel ) )
+                {
+                    // Very hackish, but just in case var is defined in system properties... try to expand it
+                    try
+                    {
+                        MavenProject tmpProj = expandProjectDefinition( project, externalProfileManager, project.getFile(), strict );
+                        Parent tmpParent = tmpProj.getModel().getParent();
+                        
+                        if ( isParentIdExpanded( tmpParent ) )
+                        {
+                            parentModel = tmpParent;
+                        }
+                    }
+                    catch ( ModelInterpolationException e )
+                    {
+                        getLogger().debug( "Unable to expand " + project.getId() + " when fetching parent from repository." );
+                    }
+                }
+              
                 // MNG-2302: parent's File was being populated incorrectly when parent is loaded from repo.
                 // keep this in line with other POMs loaded from the repository...the file should be null.
                 parentDescriptor = null;
@@ -1205,8 +1406,8 @@
                     projectId + " has wrong packaging: " + model.getPackaging() + ". Must be 'pom'." );
             }
 
-            File parentProjectDir = null;
-            if ( parentDescriptor != null )
+            File parentProjectDir = parentDescriptor;
+            if ( parentDescriptor != null && !parentDescriptor.isDirectory() ) // We test elsewhere that descriptor is a dir, test here too
             {
                 parentProjectDir = parentDescriptor.getParentFile();
             }
@@ -1371,6 +1572,227 @@
         }
     }
 
+    /**
+     * If the parent version is empty, find it in the parent-pom(s) and repair it in our project.
+     */
+    private String fixParentVersion( MavenProject project ) throws ProjectBuildingException
+    {
+       Parent projectModelParent = project.getModel().getParent();
+       String version = projectModelParent.getVersion();
+      
+        // If our project has no version, walk up our parents until we find one
+        if ( StringUtils.isEmpty( version ) )
+        {
+            version = findParentVersion( project );
+          
+            if ( StringUtils.isEmpty( version ) )
+            {
+                throw new ProjectBuildingException( project.getId(), "Unable to find version in parent pom-s" );
+            }
+          
+            if ( StringUtils.isEmpty( project.getVersion() ) )
+            {
+                // If our version was being implied from the parent version, then set our version
+                project.setVersion( version );
+            }
+          
+            projectModelParent.setVersion( version );
+        }
+        
+        return version;
+    }
+    
+    /**
+     * If the parent groupId is empty, find it in the parent-pom(s) and repair it in our project.
+     */
+    private String fixParentGroupId( MavenProject project ) throws ProjectBuildingException
+    {
+        Parent parent = project.getModel().getParent();
+        String groupId = parent.getGroupId();
+        
+        if ( StringUtils.isEmpty( groupId ) )
+        {
+            groupId = findParentGroupId( project );
+            
+            if ( StringUtils.isEmpty( groupId ) )
+            {
+                throw new ProjectBuildingException( project.getId(), "Unable to find groupId in parent pom-s" );
+            }
+            
+            if ( StringUtils.isEmpty( project.getGroupId() ) )
+            {
+                // If our groupId was being implied from the parent groupId, then set our groupId
+                project.setGroupId( groupId );
+            }
+            
+            parent.setGroupId( groupId );
+        }
+        
+        return groupId;
+    }
+    
+    /**
+     * If the parent artifactId is empty, find it in the parent-pom(s) and repair it in our project.
+     */
+    private String fixParentArtifactId( MavenProject project ) throws ProjectBuildingException
+    {
+        Parent parent = project.getModel().getParent();
+        String artifactId = parent.getArtifactId();
+        
+        if ( StringUtils.isEmpty( artifactId ) )
+        {
+            artifactId = findParentArtifactId( project );
+            
+            if ( StringUtils.isEmpty( artifactId ) )
+            {
+                throw new ProjectBuildingException( project.getId(), "Unable to find artifactId in parent pom-s" );
+            }
+            
+            parent.setArtifactId( artifactId );
+        }
+        
+        return artifactId;
+    }
+    
+    /**
+     * Recurse up our lineage (parents) until we find a parent whose version is specified.
+     */
+    private String findParentVersion( MavenProject project )
+    {
+        getLogger().debug( project.getId() + ": looking for parent version" );
+        MavenProject candidateParentProject = project.getParent();
+        
+        if ( candidateParentProject == null )
+        {
+            getLogger().debug( project.getId() + ": found no parent!");
+            return null; // no more parents to chase down! User probably didn't put a version anywhere!
+        }
+        
+        String version = candidateParentProject.getVersion();
+        
+        if ( StringUtils.isEmpty( version ) )
+        {
+            return findParentVersion( candidateParentProject );
+        }
+        
+        getLogger().debug( "" + project.getId() + ": returning ver from " + candidateParentProject.getId() );
+        
+        return version;
+    }
+    
+    /**
+     * Recurse up our lineage (parents) until we find a parent whose groupId is specified.
+     */
+    private String findParentGroupId( MavenProject project )
+    {
+        MavenProject candidateParentProject = project.getParent();
+        
+        if ( candidateParentProject == null )
+        {
+            return null; // no more parents to chase down
+        }
+        
+        String groupId = candidateParentProject.getGroupId();
+        
+        if ( StringUtils.isEmpty( groupId ) )
+        {
+            return findParentGroupId( candidateParentProject );
+        }
+        
+        return groupId;
+    }
+    
+    /**
+     * Recurse up our lineage (parents) until we find a parent whose artifactId is specified.
+     */
+    private String findParentArtifactId( MavenProject project )
+    {
+        MavenProject candidateParentProject = project.getParent();
+        
+        if ( candidateParentProject == null )
+        {
+            return null; // no more parents to chase down
+        }
+        
+        String artifactId = candidateParentProject.getArtifactId();
+        
+        if ( StringUtils.isEmpty( artifactId ) )
+        {
+            return findParentArtifactId( candidateParentProject );
+        }
+        
+        return artifactId;
+    }
+    
+    /**
+     * Return true if there are no more variables to be expanded in a model's parent tags.
+     * 
+     * Note that this will also return false if there is a variable that simply cannot be expanded because it is not defined
+     * or was misspelled, etc.
+     * 
+     * @param parent a model's parent tag
+     * @return true if there are no more variables to be expanded in a model's parent tags.
+     */
+    private static boolean isParentIdExpanded( Parent parent )
+    {
+        return ( !StringUtils.isEmpty( parent.getVersion() ) &&
+                 !StringUtils.isEmpty( parent.getGroupId() ) &&
+                 !StringUtils.isEmpty( parent.getArtifactId() ) &&
+                 parent.getVersion().indexOf( "${" ) == -1 && 
+                 parent.getGroupId().indexOf( "${" ) == -1 && 
+                 parent.getArtifactId().indexOf( "${" ) == -1 );
+    }
+
+    /**
+     * Return true if there are no more variables to be expanded the tags that comprise an artifact definition.
+     * 
+     * Note that this will also return false if there is a variable that simply cannot be expanded because it is not defined
+     * or was misspelled, etc.
+     * 
+     * @param model the model to inspect
+     * @return true if there are no more variables to be expanded in the definition of a model's artifact.
+     */
+    private static boolean isModelIdExpanded( Model model )
+    {
+        String version = getModelVersion( model );
+        String groupId = getModelGroupId( model );
+        String artifactId = model.getArtifactId(); // should never be empty/missing
+        
+        return ( !StringUtils.isEmpty( version ) &&
+                 !StringUtils.isEmpty( groupId ) &&
+                 version.indexOf( "${" ) == -1 &&
+                 groupId.indexOf( "${" ) == -1 &&
+                 artifactId.indexOf( "${" ) == -1 );
+    }
+    
+    /**
+     * Sometimes a model's GroupId is specified only in its parent. Fetch whatever we can find.
+     */
+    private static String getModelGroupId( Model model )
+    {
+        if ( model != null && model.getGroupId() != null )
+            return model.getGroupId();
+
+        if ( model == null || model.getParent() == null )
+            return null;
+        
+        return model.getParent().getGroupId();
+    }
+    
+    /**
+     * Sometimes a model's Version is specified only in its parent. Fetch whatever we can find.
+     */
+    private static String getModelVersion( Model model )
+    {
+        if ( model != null && model.getVersion() != null )
+            return model.getVersion();
+        
+        if ( model == null || model.getParent() == null )
+            return null;
+        
+        return model.getParent().getVersion();
+    }
+    
     private static String createCacheKey( String groupId, String artifactId, String version )
     {
         return groupId + ":" + artifactId + ":" + version;
Index: maven-project/src/main/java/org/apache/maven/project/artifact/ActiveProjectArtifact.java
===================================================================
--- maven-project/src/main/java/org/apache/maven/project/artifact/ActiveProjectArtifact.java	(revision 510454)
+++ maven-project/src/main/java/org/apache/maven/project/artifact/ActiveProjectArtifact.java	(working copy)
@@ -49,6 +49,8 @@
 
     private final MavenProject project;
 
+    private String modelRepresentation;
+
     public ActiveProjectArtifact( MavenProject project, Artifact artifact )
     {
         this.artifact = artifact;
@@ -296,4 +298,14 @@
     {
         artifact.setOptional( optional );
     }
+
+    public String getModelRepresentation()
+    {
+        return modelRepresentation;
+    }
+
+    public void setModelRepresentation( String modelRepresentation )
+    {
+        this.modelRepresentation = modelRepresentation; 
+    }
 }
Index: maven-project/src/main/java/org/apache/maven/project/artifact/ProjectArtifactMetadata.java
===================================================================
--- maven-project/src/main/java/org/apache/maven/project/artifact/ProjectArtifactMetadata.java	(revision 510454)
+++ maven-project/src/main/java/org/apache/maven/project/artifact/ProjectArtifactMetadata.java	(working copy)
@@ -80,20 +80,34 @@
         File destination = new File( localRepository.getBasedir(),
                                      localRepository.pathOfLocalRepositoryMetadata( this, remoteRepository ) );
 
-        // ----------------------------------------------------------------------------
-        // I'm fully aware that the file could just be moved using File.rename but
-        // there are bugs in various JVM that have problems doing this across
-        // different filesystem. So we'll incur the small hit to actually copy
-        // here and be safe. jvz.
-        // ----------------------------------------------------------------------------
-
-        try
+        if ( artifact.getModelRepresentation() != null )
         {
-            FileUtils.copyFile( file, destination );
+            try
+            {
+                FileUtils.fileWrite( destination.getAbsolutePath(), artifact.getModelRepresentation() );
+            }
+            catch ( IOException e )
+            {
+                throw new RepositoryMetadataStoreException( "Error writing POM to the local repository.", e );
+            }
         }
-        catch ( IOException e )
+        else
         {
-            throw new RepositoryMetadataStoreException( "Error copying POM to the local repository.", e );
+            // ----------------------------------------------------------------------------
+            // I'm fully aware that the file could just be moved using File.rename but
+            // there are bugs in various JVM that have problems doing this across
+            // different filesystem. So we'll incur the small hit to actually copy
+            // here and be safe. jvz.
+            // ----------------------------------------------------------------------------
+
+            try
+            {
+                FileUtils.copyFile( file, destination );
+            }
+            catch ( IOException e )
+            {
+                throw new RepositoryMetadataStoreException( "Error copying POM to the local repository.", e );
+            }
         }
     }