At WWDC I introduced the Madsonline Power Bank. One of the developers will take it to "Burning Man" for his electrical needs there. The Power Bank is a 24 or 36 amp hour external lithium polymer battery. One can charge it using an ac adapter or a solar panel. Voltage outputs are USB/5V, 5V, 8-12V, 15-16V, and 18-20V. You can power just about any device except the iPhone. We are working on this. Today, I was able to charge and run a 17 in MacBook Pro as I am now able to get some MagSafe Cables. The 24 amp hour battery will power the MacBook Pro 4 X longer that the internal battery. The 36 amp hour is 9 X. One really has mobile freedom with a Power Bank and a Verizon air card. .
Madsonline Power Bank 