OK, was planning on discussing this w/ y'all next week.
One thought I had was to create a JndiBindingPolicy chain to allow N bindings for each type. For each policy in the chain we get the target binding. Then we flatten out the results and bind each. This gives us the backwards compatibility of the current BasicJndiBindingPolicy and allows us to add in SpecCompliantGlobalJndiPolicy. In case of conflict==descriptive deployment error.
Would require backwards-compatible changes to jboss-metadata, but these should be allowed as they're not dependent upon any new spec revision and are just some normal enhancement.