If you'd be interested in doing a 68020/030 backend for LLVM on the Amiga the Mattathias team might have some use for you. We are working on a compiler generation program based on PEG syntax and could use a little help with that also. The first goal is to produce an Amos Basic Professional-compatible compiler for LLVM-compatible platforms. (We'll probably be using Simple Directmedia Layer (SDL) for the non-Amiga Classic systems.)
To contact team Mattathias, our Yahoo group mailing list is at
http://tech.groups.yahoo.com/group/mattathias/ and the website for LLVM is
http://www.llvm.org where they have their mailing lists at the bottom left end of the page.
I hope we can work something out together!