http://cleantechnica.com/2010/02/11/ls3-all-terrain-military-robot-mule-could-play-a-green-role-too/
LS3 Robot Mule, will be able to follow a soldier and get up and down rough terrains while carrying a heavy load, and looking like the Walker for Star War all at the same time.
Even in a robot, one set of legs has to carry stuff backward. 
Cool, but I wonder what the benefit of the front pair of legs being backwards is.
i think it is easier to balance with legs like this. each set of legs acts can counter forces from the other set in a full range of motion. if they bend both to the same direction, then when one set of legs lose control, the best other set of legs can do is to straighten and depend on the body to shift the center of gravity backwards in order to come to a full stop. that might still be a bit too difficult for the robot. or maybe there’s just no reason to do it.
in the natural world, horse, sheep and deer front and back legs bend to different direction as well. but they have the from bend forward and the back bend backward. as oppose to big dog, having the front bend backward and the back bend forward. maybe that’s why bigdog looks so strange to us.