Found another controller today, the MoJo and HAPP100. Celtic Magic is a company that designs this equipment for people with limited use of their limbs. With these devices they can operate computers, game machines (consoles, PC, Mac etc.) and other assistive aids.
These devices are comparable to the Quadstick, usually the most used device. However with the HAPP100, a breath controller you can control a computer with breath, having total mouse control and type using an on-screen keyboard.
The MoJo(Modular Joystick System) you can control games. It uses sensors you can put on any part of your body. Makes it different from Sip ‘n Puff and might be a solution for you?