Here's something odd that i found couple years ago and that i trade, it's the only picture of it (maybe i have other in some backup somewhere...) anyway. DP also have this one on his database.
This chair called "Hot Seat" have a sensor under it for the directions, the joystick mounted on the left side have A,B,Start, Select and turbo button.
Basically, you have to move yourself and the character on screen will go to the right for example.
From what i remember, the sensor wasn't very accurate for quick change (like playing Rad Racer was impossible).
The size would fit a kid or a small adult (5'5")