Due to the direct coupling of the bar to the torque tube, the movement becomes amplified the longer the bar is.
Hitting your chest and passenger in the back would be a real problem.
The only way I can see this working is to use an "A" frame set up with training bars fitted like a trike.
This would only then leave your feet free for the placement of the throttle.
If I was goint to do this, I would buy and convert a Trike.
Sam