Good thread packed with useful information. but the original premise is a little nutty, why would you want to trade in a place with no access to electricity?
its called 'monitoring the market'. Anyways it looks like the new intel chips are gonna increase battery life big time. The new Toshiba laptops are all coming in 7+ hrs on Sandy Bridge.
I bought my Asus laptop just for this. It has an advertised battery life of 11.5 hours, but I have never gotten that before. I can get 8-9 hours while actively trading with the screen brightness cranked down. Plus the wood trim is pretty nifty. http://www.amazon.com/U43JC-X1-14-Inch-Bamboo-Laptop-Battery/dp/tags-on-product/B003V4AK4I
The SANDY BRIDGE ASUS CUSTOMIZED EZ LAPTOP will do this. The laptop comes with an SSD Drive and once all the trading stuff is loaded into memory the computer wont go back and forth to the drive http://tradingcomputersnow.com/laptop-trading-computers/