I think this is a bit far fetched, but I like the idea of something similar. Have rental stations with trailer hitch gas generators that I can pull along for longer rides. Turns every EV into a Chevy Volt.
Or would the weight be more than a (future model) Leaf could easily be designed to pull?
The gas range extender though means that you can take your EV on a road trip and refuel in a matter of minutes. Overnight you charge, but during the day, you fill up along the way.