I think the pushing down cylinder would be good as a featherer for front brakes as rowan said, its not the strongest movement the human finger can do. I've just been "air-braking" now and seen that it is possible though. Forgive the shite anatomical terms here, but when people brake with a normal lever, they use the "last" part of their finger which naturally curls up when you try to pull it. The pushing down lever would simply use the next segment down on the index finger, which is curled up and almost gives a grip to the lever? I don't know maybe Im over thinking it. I can see what rowan means though, the pushing down bit is not going to be nearly as poweful as the normal levery bit, but still I really like the idea. Id almost like to try one