STV runs pretty well in MAME. On my 2.66ghz Core2 (OC'd E4400), I get like 93% in VF Kids and practically 100% in Radiant Silvergun, Cotton Bommerang, and Die Hard Arcade, and that's all software rendering. They just added an SH-2 dynamic recompiler, so your mileage may vary.

Not sure how well MAME's support is ported over to mess, or how complete the emulation is, but it seems to run fairly well.