MasterGear by Marat Fayzullin is a Master System, Game Gear, SG-1000, SC-3000 und SF-7000 Emulator for Android. The emulator is in currently in beta testing stage and therefore free of charge.

Thanks to http://www.aep-emu.de/PNphpBB2-file-viewtopic-t-17220.html for the news.

https://market.android.com/details?id=com.fms.mg