hm, that gives me an idea, yes, another idea. Would it be possible to make an AC adapter that plugs into the USB port on the book port, and charges it as you listen? You would of course have to have rechargeable batteries, but you could also just take out the batteries and leave it plugged in so you wouldnt use any battery life. I find this one of the only advantages other mp3 players have over the book port, other than shuffle/repeat functions, and it would be great if this were taken care of some day.
