During the last year the MAME team had some breakthroughs in emulating the SH3 hardware new CAVE games run in. With some unorthodox(to MAME's philosophy) hacks to improve performance or generate slowdown it is said that games were even somewhat enjoyable(I never personally bothered to try out). But then CAVE supposedly sent in a C&D and the SH3 drivers were pulled out of their repository and latest releases.
The ROM dumps for the games are still out there, so must be the MAME releases that supported them, if you're interested in it.
There was also a russian, I think, team working on SH3 emulation on their own emulator, but I don't remember what happened to them, nor do I remember whether they actually released anything but videos of the thing running.