Hey Smokey, I should be so lucky!
You're probably right, it is a good idea. In testing the circuit I did notice that with the motor is was sputtering along. As the duty cylce of the pulse increases though it becomes a smooth ride.
Also increasing the frequency of the PWM will reduce the jerkiness of the motor, this is something I will try out. With this mod the motor will almost become a stepper motor at the lower end of the duty cycle of the pulse.
Keep in mind that the design is primarily for steering purposes so a clean square wave pulse (with a variable duty cycle) is sufficient for a variable steering control.
Great ideas guys, keep 'em coming.