This is my next to last controller project:
Spinner/Wheel + 2 Trigger JoystickYou can play all spinner games (including Heavy Barrel/Ikari Warriors) and racing games by replacing the spinner knob with the racing wheel (and you can also use the joystick as a shifter).
Note: There is enough space under the wheel to use the buttons if you like.
Placing it next to my other controller (
http://forum.arcadecontrols.com/index.php/topic,132544.0.html), i am also able to play games like BattleZone.