[Christ]

for a nice electric self contained drive unit, see "reach truck". The drive and steering units are in the same self contained area. Could be made to fit just about anything else, although they haven't ever been designed with too much power or speed (about 15 mph tops, IIRC, due to the relatively tiny, solid tire used.)

Some of them have had the drive and steering wheels placed on opposite sides, with the drive wheel acting like the front wheel of a shopping cart as far as lateral movement, but still being capable of driving, while the steering wheel freewheels, and can be powered to move laterally.