Meet the 4WD IG52 All Terrain Robot: a kit with IG52 24VDC 82 RPM gear motors, Sabertooth dual motor driver, Spektrum transmitter and receiver, battery charger, and everything you need for your projects. It has a max speed of 3 mph, weighing 86 lbs.
The robot has a 100 lbs payload capacity, so it can technically be used to carry a person.