For the SNES fans who aren't already using Higan (why not?), I've committed a fix to MAME to differentiate between the SuperFX 1 and SuperFX 2, allowing Stunt Race FX, Star Fox, et al to run at the correct speed. So MAME now joins the ranks of SNES emulators circa 1999. Yay?
As an aside, I just took Super Mario RPG for a spin, and even though the softlist hash file lists it as "supported='partial'", it fired up, played just fine through the tutorial, and ran through attract mode. No text-box glitching either, which plagued early SNES emulators.