Some FRBR and FRAD-related stuff was posted by the Resource Description and Access people that you’ll want to look at.
First, in the Scope and Principles section of the RDA site there are updated mappings from FRBR and FRAD to RDA and back. They go through all of the RDA elements and tell you which FRBR entities, attributes and/or relationships they match. Important stuff.
Second, at RDA Online, which is where the actual commercial online RDA system will be, they’ve posted a new set of entity-relationship diagrams for the FRBR entities that are more visual: look up Manifestation or Concept, for example, and they’ll tell you all of the attributes those entities have, where they come from in FRBR, and what RDA elements those match. These diagrams don’t cover the relationships betweem the different entities, but there’s a placeholder so I expect they’ll come along soon.
Combined, extremely useful stuff for anyone digging into RDA, and also for anyone thinking about FRBR implementations and piggybacking on what RDA is putting in place. RDA will be a commercial product, though, and I worry about that and what effect it will have.