The reason for suggesting Pocket PC devices is basically cost and flexibility - you can get something useful for under 200 pounds sterling. I'm already using a "big" PC to edit the midi files; I dont need a hardware sequencer and the idea of being able to stream files straight onto a Pocket PC for use in the field is appealing.

Certainly the use of mp3 playback gets you into some very small hardware, but then I've got no hope of viewing the lyrics.