There ain't none. The two major 68k Mac emulators are Fusion and Shapeshifter, both are great for emulating up to OS8.5 (?).
There's only one PPC mac emu, called FusionPPC. It only works on CyberstormPPC cards and is OS9.x maximum AFAIK. I saw it on sale for ~70EUR somewhere recently (vesalia? KDH?).
-edit-
D'OH
I was talking about Mac on Amiga emu...you were asking the other way around :-D. I have no knowledge of that I'm afraid.
