My only question would be what the options for audio input are on the GP2X as I'm not aware of it being a Firewire or USB host.
The GP2X docking station allows you to plug any USB device that you want into it, and of course - whatever Linux 2.4.x supports, works:
http://www.gp32x.com/board/index.php?showtopic=33095&hl=breakoutPicture softsynth/sequencing/sampling/MIDI control center applications on that hardware? Me too ..
-- ; Jay Vaughan