I'm sure most of you are aware of the Megaplay and C/C2 based arcade systems that are based on Genesis hardware (or the other way around).
There are also at least three systems emulated by MAME that use 'pirate' Genesis chips. The only one that works correctly is Puckman Pockimon. It does not have a Z80 though.
Yanton (pretty well known in the Neo Geo community) sells these boards for $68 each
http://www.arcademvs.com/pcb/PCB_pacman.htm
I did a quick port of Frog Feast to the system, and it worked by only changing the location of the joystick input reads. The only other thing I had to do was swap the bits around. (If anyone is interested in this, I will upload it). It doesn't have sound yet, but that looks fairly easy to implement, I think.
I am waiting to receive the board for futher testing. It will be very easy to test software on the system, since it uses common eproms, such as the 27040 and 27020.
Arcade hardware based on the Genesis.
Here's a page about the hardware:
http://devster.monkeeh.com/sega/radica/
http://devster.monkeeh.com/sega/radica/