Maybe it is just me, but is this really a deal? Root your phone, use a ROM that underclocks the CPU in off mode, and when you are in a place of crappy service, aeroplane mode, or turn off the mobile network...
It isn't that hard.
Was just on a trip with 16 people in one house. Most our days were spent outdoors. Charged my iCarrier once on the 29th and it still holds a charge today on the 2nd. I've been able to keep my phone up and running the entire time. (No rooting, no underclock nonsense, no airplane mode required)