The best solar thing for survival is PowerFilm. But their retail products are quite expensive and aren't exactly flexible (I mean, not customizable to the particular task).

I wanted something not larger than my PDA in plane folded. So, I've got 7 of these PowerFilm scraps http://www.powerfilmsolar.com/products/oem_components/modspecs/mpt675.htm (but with a slightly better specs than those on the site) of eBay for around $6 each. The 7th piece was for free actually, so it was something like $40 shipped in a plain envelope.

Initially I had some thoughts of making a fancy folding cloth holster for them, but later decided that it is not necessary. First of all it's an emergency charger, I wanted it to be as lightweight as possible. Then, I've found that the panels are quite rugged just by design. And lastly, I've invented a nice way to connect them to each other without adding any noticeable bulk, and allowing a great flexibility of powering options (I can connect them in several different ways to set the required voltage).

The most challenging thing is the output voltage regulation. But in my case, I'm carrying a PowerBank device anyway, which can be charged from any 10-25V DC source. So, a good voltage regulator is integrated in it already (along with a 3800mA/h 7.2V battery, digitally regulated output 1.5 - 12V in 0.5V steps, and a bright LED floodlight - all in the size of a pack of cigarettes).

The rest are some connectors, wires, a back flow eliminating diode, and a simple 5V regulator circuit, which I've made with just a couple of capacitors and LM7805 (see here). Everything is stored in a heavy duty zip-lock bag as a kit (I need about 3 minutes to assemble the proper charger for the task if I need to).