This is a pretty simple product, though one we don't see enough of on the market. A little bigger than a hardcover book, the MFUEL Universal Power bank can charge 2 portable electronics products anywhere. It comes with a bunch of adapters that should cover most of your needs and uses Lithium-ion power that it gets from a laptop or another charger. Should retail for about $300.
MFUEL UNIVERSAL POWER BANK [CES Innovations]