Odex 1, from Odetics, Inc. walks on six legs, and weighs in at 370 lbs.  Capable of reconfiguring its shape to be tall and slender or short and squat, and able to walk in either configuration or anywhere between the two.  Each able to lift 400 lbs, the "legs" are versatile enough to be used as manipulators as well.  Odex is capable of lifting over 2,100 lbs vertically, or carrying over 900 lbs. at normal walking speed.

Sept/Oct 1983 Robotics Age Magazine Article about Odex I (approx. 1.2MB zipped)