Perpetual PDA Power? Possibly.
robb_c sent us this story about new high-efficiency power systems for portable devices - high-efficiency solar cells plus some sort of fuel cell system to store energy. Very nice, if it works, doesn't cost some ludicrous amount to manufacture, and doesn't explode when you drop it.
I want a clockwork PDA! You can already get clockwork radios and flashlights, why not a computer?