The iPod Mini sucks the juice like crazy. It’s annoying in training, but will run dry on tour day. Not that it necessarily will get much use that day. Still, I would like the option. These are the links I found on making your own solar charger. It looks pretty simple.
Commercial chargers are $60+ and more likely $100. USB cables are 5V @500mA (2.5W). Some of these commercial ones only put out 5V @100mA (.5W). I’m not certain this would run the iPod for an extended period of time.
It should be simple enough to find a 5-6W small panel. The regular assumption is 50% of the max rated. Or 2.5-3W. Should be good enough for most small devices.
http://www.reuk.co.uk/Solar-iPod-Charger.htm
Update: 6/1/2008
Parts are ordered. Should be pretty easy to build. Had to ride w/o the iPod Monday, because it didn’t have a charge left.