I saw a picture in a thread on adapting a bike to a person with one hand.......One person had a twist grip shifter mounted on a very short bar. Your might be able to rig something like that up...but it probably wouldn't look clean unless you had something machined...like a clamp on front derailer type of clamp attached to handlebar size tubing just long enough for the twist shift.......I have no idea about cable angle requirments etc......