Wow! I love all of this excitement over such a geeky technical topic!
I response to the recent inquiries, I'd say that your best bet for getting really definitive answers (and maybe even some additional guidance) would be to send Apple's Darwin team a question on their Q&A site: http://developer.apple.com/darwin/news/DarwinQA_TOC.html
It looks like they've been pretty responsive in the past.
I'd imagine that the OpenDarwin team would also be more than happy to respond with some words of advice. (http://www.opendarwin.org/) Try joining the mailing list. If you get some good answers, please post them here for everyone.