I've been compiling a lot of extension to FOAF for the FriendBlab project. I'm simply amazing that FOAF doesn't have most of this stuff. And there's lots more to come. Ten plus years of FOAF and we have a half baked spec with massive amounts of holes the size of Lake Michigan. Anyhow, feel free to use my extensions. Some of which, I believe, break the RDF model. I couldn't figure out how else to extend FOAF while preserving it and still allow my extensions to be extended. I guess that's the problem with trying to jam everything into tuples. It becomes increasingly difficult to build up, without starting all over.