That is way too much money but it is a cadillac , no doubt.
I've always wanted to build an electric push-trailer that is charged with a generator in the same way. Here in Ontario only electric is allowed and that is why I love this idea.
There are a few "motorized push-trailers" on you-tube if anyone is interested. There is even one guy that will be selling a one wheeled push-trailer that uses a 4 stroke engine.
Another way to go would be to pull a small trailer on an electric bike. The trailer would have the generator which is charging your batteries as you ride along.
I think that for me, an electric push-trailer with an on board generator would be be my dream.
Here is a link for a cool idea:

YouTube - Motorized bicycle motor.