Here are a few Controller Prototypes I have made for FPS style games

first one uses a trackball for aiming, there is a small pcb board with an optical sensor and some other components in the place of the right joystick, it uses the rest of the original controller hardware.

the 2nd controller is a standard controller with the joystick extension

the 3rd controller has a gyro sensor and built in projector, this prototype also includes duct tape.