Looking for robot motor control

[eovnu87435ds]

Does anybody know of any robot motor controllers (brushed) that have interface for a potentiometer so that it works like a servo? something like this:
http://www.luminarymicro.com/jaguar

It is so that we can have a powerful steering setup in the RC Barbie Jeep without getting a rediculously powerful servo. instead, I have the stock drive motor, a 540 size brushed motor(i think it's ~1250kV) through a 147:1 gear reduction, with a pin in it that will move the wheels.