This isn't as nice as your recommendation / idea but here is another product available from Photojojo.com for $149.9
The Power Pot: A Fire Powered USB Charger
Harness the power of flames to charge your phone
You're sitting around the glow of the campfire, looking all rugged and outdoorsy, but when you pull out your phone for a selfie ... disaster! Dead battery.
You need the Power Pot. It charges your phone using thermoelectricity magic while you simultaneously heat up a pot of food to charge your tummy.
If you can build a fire (or, better yet, fire up a camp stove) you are well on your way to a no-outlet-necessary phone reboot.
Don’t miss photos ops of morning tent hairstyles or bears creepin' on your turf.
Plus, the Power Pot is so light you'll barely notice it on the hike.
Bonus: should bigfoot attack, the Power Pot will give you the charge to tweet pics and a bowl of soup to befriend him.
Charge your phone while heating up your dinner
Handle and cables are silicone coated and flame resistant
Won't add bulk to your pack. It weighs just 14oz.
The lid doubles as a second pot
Stay in touch while getting in touch with nature
Made to be tough, it includes a lifetime warranty
We took the Power Pot camping in Big Sur. See our photo story of the trip!