After discussion in #maven, it seemed that this plugin could be of use by the general population.
It manages the buildnumber for a specific project, and even can produce an (optional) buildclass.
example setup.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-buildinfo-plugin</artifactId>
<version>1.0-alpha-1-SNAPSHOT</version>
<configuration>
<infofile>.buildinfo</infofile>
<classname>org.codehaus.modello.plugins.dom4j.BuildInfo</classname>
</configuration>
<executions>
<execution>
<goals>
<goal>buildnumber</goal>
<goal>buildclass</goal>
</goals>
</execution>
</executions>
</plugin>
http://commons.ucalgary.ca/projects/maven-buildnumber-plugin/