Haven't had a chance to write about the recent work that was recently introduced in those projects.
On the RubyCocoa front, libffi is now used everywhere, more specifically when branching new pure Ruby method implementations (using closures). This fixes some weird bugs related to floating parameters that were not properly handled when passing from ObjC to Ruby. And this removes the last place where NSInvocation was used, which is good for the performances. I'm going to do some benchmarking against the previous implementation in a couple of days, I will post the results.
On another side, the bridge support XML format was refactored and now describes more things like ObjC informal protocols. This removes the DummyProtocolHandler mechanism, and indirectly the last thing that was generated at build time (which is good for maintenance). The XML format also describes some kind of exceptions, like C-array-like arguments whose size is delimited by some context at runtime (like the value of another argument, or terminated by NULL, or with a fixed size, etc...). Problematic methods include for example [NSArray +arrayWithObjects:count:], or [NSBezierPath -appendBezierPathWithPoints:count:]. These exceptions can't be determined automatically though, that's why they are kept in a separate file that is read by the gen_bridge_metadata program when generating the final metadata file.
All this work is available in a new unstable branch, and appears to be stable enough to be tested. I consider releasing the content of this branch as a developer preview in the very near future.
About RubyOSA, as I said previously it's almost ready for a first public release (modulo some things that I would like to support first, like timeouts and unicode strings). Some people are even seriously using it. I plan to release the first version in a couple of days. In the meantime, the website is up!
I will be in the SF bay area next week (until Thurday, then I flight to Denver for the promising RubyConf where I will talk about Ruby on Mac OS X). If you want to meet drop me a message, I will have some time to spare in the evening.