so far, our 2 major ideas for steering is to get a 1/4 scale servo and plug it into the rack n pinion type steering, or use this motor we have, with a belt that will go around the steering wheel of the jeep.
http://banebots.com/p/M4-R0062-12
so its basically pay 25 bucks, and have alot of fun mounting a servo in the middle of nowhere in the jeep, or rig the motor idea, which probably will not be very reliable.