Alternately, instead of a knee lever (which might require a specialty stand to accommodate it), I would suggest something that was on my old Yamaha D80 home organ many moons ago: a lever incorporated with the expression/volume pedal that is mounted to the left side edge of the pedal. It was activated by simply pivoting your foot slightly to the left while having your foot on the expression/volume pedal. As I recall, on the organ, it had 4 functions: sustain (like piano damper), pitch bend (it was limited only to a semi-tone in one direction to simulate Hawaiian guitar pitch bending), arpeggio on and off, and one other function that I am not sure of at this time -- maybe rhythm/style on and off.
I imagine that on a modern keyboard like a Genos, a knee bar or volume pedal lever could be programmed to do dozens of functions.
Something like that would be cool for any keyboard, but I'm not sure how it would hook up to something like a PSR-E series that doesn't have a dedicated multi-functional jack. Maybe something could be controlled through one of the USB ports, or at the very least, it could just take the place of the sustain pedal, which on the E-series can be programmed for 3 or 4 different functions.
