I found this as an alternative to Scott's robot sherpa post
Bionic legs give soldiers a boost
US researchers have developed strap-on robotic legs to allow people to carry heavy loads over long distances.
The Berkeley Lower Extremity Exoskeleton, or Bleex, is part of a US defence project designed to be used mainly by infantry soldiers.
The device consists of a pair of mechanical metal leg braces including a power unit and a backpack-like frame
see it here: http://tinyurl.com/l6o6v
I wish I could have one