Just arrived on the market.
http://www.poweritanywhere.com/powerpackintro.shtml

Seems to be good for prolonged storage while not activated.

Interesting--a portable fuel cell. I wonder if you can fly with it? Didn't say anything in their FAQ section.

They seem to be pretty vague about shelf life and how long it lasts once activated.

I remember hearing about these last year. Shelf life was one of the selling points back then. This was pre-production of course but they claimed the cells which fuel the pack were good for 10 years on the shelf.

I don't recall if this is from the same company or not.

Further reading on their site shows that Medis is specializing on hybrid fuel cells. So, inside of this device one can find a regular Li-Ion cell to maintain peak power, plus some methanol charging cell in parallel to it. Logically thinking, the shelf life of this pack is probably not that great (same as of a regular rechargeable Li-Ion's).

Sent a message to Medis asking for more technically sound specifications. Will keep your posted