Tharos has updated his Chip8 Emulator for the GP2X:
Version 0.1 allows to map the controlls different for each Chip8 game (as Chip8 has often a very strang keymapping). Have a look at the readme.txt and the keymappings files which explain how to do own keymappings.
Download From Here --> http://gp2x-emulation.dcemu.co.uk/efcs2x.shtml