RZ, Just like Dwight - if you find a brake switch from any old wreck, it's just a matter of welding or bolting a bracket in front of the top portion of the brake pedal. When the pedal is pushed down, the switch "opens". As such, there's really very little pressure or load on the switch, so you won't have to go crazy with an over-engineered, TIG welded masterpiece.
It sounds so easy, but I still had a friend do it for me....
