Powertraveller already has a well-stocked line of portable solar chargers aimed at outdoor excursionists. The company hails from the sometimes-drab, bitter UK, so it's not surprising that it'd want to develop a charging option that doesn't rely on the shining sun. The Powermonkey Expedition offers several.
The Expedition is based around a tubular, aluminum-cased lithium-polymer battery with a capacity of 10,500 mAh. That's not quite as large as Powertraveller's ginormous 60K Silverback-Gorilla, but the company reckons it's enough to charge the iPhone 5 about seven or eight times. That's way more than the average work commuter needs, but like its name implies, this unit is designed for lengthier trips, far away from the bedroom electrical outlet.