In amateur radio land, we use the biggest thing we can find. Surface area is everything. Roll up panels, like these:
http://www.powerfilmsolar.com/products/?...ategoryIDs=6578

....is what I would carry, but you will spend $300 or so for them. Wind is another option. Tiny portable windmills are easy to cobble together.

That said, I try and leave home all the electronics I can. Even flashlights will be coin cell versions. I still like map/compass nav over GPS. Cell phone, maybe, left off most of the time, and left home if no service is available. I've hiked ham radio gear in and made contacts in very remote places, and that's where I'd use the big, roll up, chargers. Remember, they are worthless on cloudy days or at night. Sometimes just a bank of lithium batteries, like some of the new car jump starters, will power your stuff for weeks and weigh less than a solar panel. I own this one for my motorcycle, and have started many cars with it...downright amazing for it's lightweight and size. Has lights and will charge your phone many times.
http://www.geniuschargers.com/boost/