Unofficial OSX Port of VOPM 0.15 (latest Windows version and source release is 0.17) and english manual here:
http://www.gorenfeld.net/lou/audio.php3

Free VSTi host for OSX here, works with VOPM:
http://www.refusesoftware.com/freeware.html

I've uploaded an unoptimized, patched SDLMAME binary for OSX:
http://www.mameworld.info/ubbthreads/showthreaded.php?Cat=&Number=182003&page=0