(preferably those that roll up) ... that would be useful.
I saw a lot of positive reviews for PowerFilm when been researching the subject some years ago: http://www.amazon.com/PowerFilm-Rollable-Solar-Panel-Charger/dp/B001UHAAAC - still on the market - means they are good. Just look around for deals. On other hand, foldable options are also good. The Nomad I have is extremely tough and has a very well thought out design:
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