in my experience, an 030 at 50mhz is around 9mips (Blizzard 1230IV)
I've also tried an Apollo 1240 040 at 33mhz, that clocked in at 20mips,
However you probably won't see much difference unless you have a graphics card, or like 3D games.
Robert
Edit: Ref Elbox and the SharkPPC cards, don't hold your breath as we've been waiting years and years for those.