You may have seen one of these neat forklifts on Mythbusters — the Airtrax Sidewinder ATX-3000, now being built and marketed by Vetex, uses Mecanum wheels to give omni-directional mobility in a lift truck. The Mecanum wheels, invented by Bengt Ilon when he was an engineer working for Mecanum AB, have a series of tilted elliptical rollers around the circumference. This allows normal forward and backward motion like a conventional wheel, but also provides sideways motion (by rotating the wheels on the front and rear axles in opposite directions).
On the Sidewinder, each wheel is a steel hub with 12 polyurethane-coated rollers. The operator controls forward, backward, sideways, and rotational movements using a traction joystick. All the lift, tilt, and auxiliary hydraulic movements are controlled by a second joystick. The electric Sidewinder has a load capacity of 3000 lbs. I was not able to find out what a new Sidewinder costs, though an expired online listing for a used one had a price of $15,000.
SIDEWINDER Lift Truck [Manufacturer’s Site]