Panasonic recently released their "evolta" alkaline cell:

http://www.ecofriend.org/entry/panasonic-s-evolta-world-s-longest-lasting-alkaline-battery/

Of course, the claims are substantial, but because this is a new product it will be a while before anecdotal evidence proves or disproves the manufacturer's claims.

I haven't seen any yet (and I am currently in Japan) but I'm keeping an eye out for them.

Cheers,

A