This sounds great; I just hope that at the end of that 40 hours, there'll be some hydrogen or liquid methanol lying around to recharge it...

Dude, Ethanol fuel cells are right behind.
The Liquor Laptop is right around the corner. No more messing with tangly power cables when a slug of Johnny Walker poured into your powerbook does the deed.

Can we have a 20-hour fuel cell in a year instead?

Or a two hour fuel cell, but I can just squirt more fuel cell stuff into it from my handy-dandy fuel cell container and get two more hours?

I wonder what the limiting factor is? Because honestly I can carry around a pretty big bottle of whatever fuel it requires if I need to. I was talking about this with a coworker once. I already have to carry around a laptop case, etc. What if the bottom 1 inch of the carrying case was just a fuel container and I plug a hose from there into the laptop?

Alternately, what if the carrying case has the fuel cell itself in it? it could be made larger and with a larger capacity and I could just plug a DC cord straight from there into my laptop.

Well, if it is methanol, that's not too hard to find at a
hardware store, but the airlines may not want you bringing a
gallon on board. Then there is the issue of the waste/exhaust.
A hydrogen fuel cell just has pure water coming out, but other
fuels will have more waste. Johnny Walker from the beverage
cart will probably leave a big mess.

This is starting to sound like laptops with digestive tracks.

Just don't let them get a test for meat and we should be OK.

er, taste. Taste. That is all.