I did an experimental port of Handy a few years back. It doesn't run at full speed even on a 100MHz 060 (maybe 50% tops).
The CPU is only part of the problem; even if it's possible to emulate the CPU at full speed, the rest of the hardware needs to be emulated as well. The ST is really simple in this aspect, other architectures are not (especcially when it comes to games consoles).