Stumbling upon "fragment" request from a user (http://community.jboss.org/thread/149627),
I remembered Adrian mentioned that this (fragments) should be handled at deployers level, as some sort of sub-deployment.
Thomas' initial version changed VFSCLPolicy, which was too invasive (http://community.jboss.org/thread/146751).
Current version supporting this extends VFSCLPolicy and puts the fragments there.
So, Adrian, can you elaborate a bit on the fragments == sub-deployments idea?