Here's a gizmo that could come in handy. The Innovus Design Fusion Solar Messenger Bag w/ optional PowerPac is basically a messenger bag that uses solar power to charge external batteries as well as internal batteries of a bunch of personal electronics using an existing 12V cigarette lighter adapter. So not only can you throw all your electronic shit in the bag, you can use it to quick-charge them as well. No price yet.
Innovus Designs Inc - 2006 CES Innovations Award [Eclipse Solar Gear]
Purchase info for solar powered messenger bag [Shopping.com]