Yoshihiro released an alpha version of SMS360 a Sega Master System and Game Gear emulator port for homebrew Xbox360s:
[QUOTE]
Quick and simple Port from PC to XDK to let you see what can be done without an official devkit .

100% Coded on Retail :=) No Need for donations at all

Plays all sms & GG Games
all the roms go inside the smsroms folder
full screen mode
Zip Gz support
Simple rom Browser
Sound support.
SaveState Support
2 player possible .