critical has updated his port of UAE4ALL (UAE for DC) for the GP2x. Release notes:

0.3.0 has virtual keyboard support. Things have altered slightly with the mouse left and right clicks. Start still toggles mouse emulation, but the L and R buttons no longer act as mouse clicks until you’re in mouse emulation mode. R now brings up the virtual keyboard. B enters the keystroke you’re over, and L dismisses the virtual keyboard. I had a bit of bother getting it to work, I’m afraid, and there’s a hack in there for now which means that your data directory *must* be at: /uae4all/data/ on your SD card, or it won’t be able to load the bitmaps for the keys. Lame, I know, but I thought you’d be able to cope with that for now.