Stumbled upon these two products:
http://www.semsons.com/semsons-inc/unbaexwiusbp.html
http://www.semsons.com/semsons-inc/pocpowban.html
I was thinking I could use them with my digital audio player/recorder (iRiver H140) to recharge the internal battery and power the thing for long stretches at festivals.
Thoughts? Am I crazy?