Under military funding, a Califorinia company named Ultracell has developed a 25W methanol fuel cell system capable of running a rugged laptop for 8 hours at a time. Using 250cc canisters of methanol (about the weight of a can of Coke), the system can convert the methanol to hydrogen and the hydrogen to electricity.
While lugging around laptop fuel doesn't sound all that much better than batteries, this methanol system would shave 65% of the weight from what our soldiers carry now (which is a hefty 12 kilos of batteries per 72-hour mission). And if we were soldiers, we'd gladly spend that weight savings on guns and diapers. [cleantech via cnet]