There's a guy that races at Darley Moor (in the UK) he has one arm that is paralysed, he just velcro's it to the tank. He's usually in the top half of the field. Tony (X-man) may know him and have contact details. Maybe he could help you out.
Regarding the brakes, we use linked brakes on the race outfit. The lever on the handlebars only operates one of the front calipers, the other two front calipers (yes, it has 3!) are operated by the foot pedal, along with the rear and sidecar brakes.
The foot pedal operates 2 AP Lockheed master cylinders, one operates the front calipers, the other operates the rear and sidecar. All of the calipers are 2 piston Lockheed racing types, except the sidecar, which is a Honda MT 125 front caliper.
The pedal pushes onto a balance beam that has the pressure point offset so that there is a braking bias towards the front calipers. Both master cylinders are operated by threaded bars with Rose-joints on them so that they can be adjusted.
If you want any more details let me know.
This is not my bike, but it shows the same arrangement.