If you watch Josh "Jakass" Holmes' videos (I couldn't fint the exact one) he shows in one of them that he has custom made pedal shafts that allow for different gearing perspectives. He does not go into any further detail, but from what I can gleam from the pictures it seems like he has long metal pedal shafts that have multiple attachment points for the pedals along the shaft. I figure that he can quickly disconnect the pedals and move them higher or lower on the shaft, giving the feeling of higher and lower gears.
I am personally hoping that we are only a few years away from Greg Ketterman walking out of his garage with a version of the mirage drive that has mulitple gears like a bike! That is when things like a whole new racing league will take off