Shift balancer

I think it would be cool (and probable, and maybe easy) if one could take a cruise control box and shift around the inputs and outputs so that it causes engine speed to match transmission speed. The system would get turned on when the clutch is disengaged(, and the wheels are moving) and would use the actual cruise control system to determine which gear the driver was going to select next (ie whether the car was accelerating before the disengagement or decelerating.) Then, knowing what the transmission speed is/will be (this would serve as the original set speed of the CCbox) and what the engine speed is (the original wheel speed sensor would take this input) the box could then adjust engine speed to match the transmission speed=smooth shifting.