Long before the Wii Balance Board was a gleam in a developers eye, we had the Roll & Rocker, where “YOU become the directional control pad!”.
Basically, this was a controller where you stood on a board, which rested on a ball that was physically the control pad. As you tilted to each side, you pressed up, down, left, or right. To use the A, B, Start, and Select buttons, you plugged a controller into the front of the device.
From what I understand (and rightly so) it never really caught on.