While great in concept, solar powered gadgets just never seem to be very practical at the end of the day. Regen's tweak on the formula
might help a little, by stuffing a battery into the solar panel itself, meaning you don't have to keep your iPod plugged in for a painfully long trickle charge or juggle multiple elements to make it work (there's a USB plug on the side). ReNu also has batteries in its various docking accessories as well, all of which can be charged by the ReNu panel or by AC power. It's not going to turn the emerging market on its head, and at $199 for the ReNu unit by itself it's not cheap either, but it seems like a logical direction for sun-fueled devices -- and looks pretty cool doing it.
Regen's ReNu solar panel system in the flesh