Nah, I am really MUCH more interested in a "series-hybrid" trailer.
If I wanted a small engine to push my motorcycle around, I would just get a gas motor.
I am really interested in a generator set for occasional use range extension. Ideally, it would run on biofuel as well.
Using scooter or motorcycle parts to build it would be slick though.
Mr Sharky's pusher trailer was made from car parts that match his EV car. I always thought that was pretty neat.