I agree. Modular is the way to go. Ive got molex connectors coming off my ipac, optipac, and pc's joystick port. Panels are held on with industrial strength velcro so swapping is fast and easy.
This way i can swap between:
Standard 2 Player 6 button
Steering Wheel and Pedal
Tron
Trackball
Dual Steering Wheels
Paperboy
and Star Wars
and eventually, Sarge, Spy Hunter, and Terminator 2 panels.
Modular = Goooooooooooooooooooooooood!