e-beach
10 MW
Maybe on the edge of the doable.....
This solid oxide fuel cell might meet Dogman's criteria..Carrying enough propane is another issue but it is readily available.
ROAMIO D245XR
245 Watts
28 VDC
2.6 kg
L 40cm x W 14cm x H 14cm
Propane: 112 grams/hr
http://www.ultra-ami.com/portable-power-fuel-cell-products/roamio-defender-series/

This solid oxide fuel cell might meet Dogman's criteria..Carrying enough propane is another issue but it is readily available.
ROAMIO D245XR
245 Watts
28 VDC
2.6 kg
L 40cm x W 14cm x H 14cm
Propane: 112 grams/hr
http://www.ultra-ami.com/portable-power-fuel-cell-products/roamio-defender-series/