Sergey Tikhonov has been working for a few months on an Alpha port of the Mono JIT. The port can currently bootstrap itself (a sanity test that is used by all Mono ports), and the port is able to build the usual Mono GUI libraries (Gtk# and the Gtk# apps).
Currently the port still lacks varargs support, debugger support, global register usage and some peephole optimizations.
All of this code is now on SVN, and will appear shortly on the Mono 1.1.18 release.
Mark Mason has been working on a MIPS port, and he said this morning that the port is now "limping along". Not quite sure what that means until we see the patch.
Now all we need is a m68k to conquer the Atari ST world and a VAX port for all of you that still run an 11/780 in your basement.