you could use a project box from radioshack... i didnt want to use a 9V so i got a 8AA clip... rechargable 9V would be good instead of spending $1-5 on each battery...
well if you get one like the pocket pal or a MXDL it uses 3 AAAs. You could easily replace those with 10440s which give 3.6v each...so you would have to watch your voltage to make sure you dont go above 12v (assuming you are using the rkcstr driver)
yea, i was going to use a flexdrive to begin with but they were out of stock and not expected for a few weeks so i just went to look for a good 9v host