Details here http://community.jboss.org/wiki/EJBreferenceresolvers
The current state of that project is usable (most of the work was just moving the code and refactoring, so it was easy) . My next step will be to add some more javadocs and start integrating this into ejb3-core/ejb3-common in a backward compatible way. I'll also ping Marius to see if he can give this a quick try from within his Weld implementation (I guess they use these resolvers directly within their impl).