I've tidied up the project I'd been looking at a while ago and it's available to play with if you want (as demether asked if there was anything available yesterday).
It's in the file archive here:
http://www.gp2x.de/cgi-bin/cfiles.cgi?0,1,0,0,6,1413
Text from the readme:
GP2X Tracker 0.1.0...