A good naming scheme which com.springsource uses (which already has a substantial repo of wrapped artifacts) is to keep the same groupId, and adding com.springsource before the <groupId>.<artifactId>.
The package with groupId org.apache.xmlbeans and artifactId xmlbeans
would be wrapped:
There should at least be a good convention for this, that keeps the same groupId.
By default the pax-wrap archetype will use the containing module pom (ie. from the directory above) to compute the wrapper bundle's groupId, so if you use pax-wrap beneath org.foo:bar then the new groupId for the wrapped bundle is org.foo.bar - if there's no parent then it uses "examples" as the groupId.
You can also force it to use a specific groupId (http://www.ops4j.org/projects/pax/construct/help/wrap-jar.html)
-DbundleGroupId=groupId provide a customized groupId to the new bundle
The artifactId is computed by combining the original groupId and artifactId - this is done so we can wrap multiple artifacts under the same directory and maintain their inter-dependencies (see the wrapTransitive option) without worrying about any future clashes.
The reason we don't keep the original groupId by default is because only the original project is allowed to deploy artifacts under that groupId, in fact the SpringSource naming convention has caused a lot of confusion on the Maven mailing lists because it keeps the same groupId.