Hey if you want to add wind power you can always keep a small wind generator in your trunk. There's a guy on YouTube that built a van that can use an attached wind turbine when he is out camping. He also has solar panels on the roof. This thread just gave me an idea for the camper of the future. Stay with me on this.
The Volt is the main head of this beast. It's basically a third wheel but a little different. This baby has an integrated solar roof and attachments for wind turbine(s). Please don't put the wind turbines up while you are driving (because of what the other posters above mentioned).
Now I know what you are thinking, "The Volt is not strong enough." Exactly! The trailer has it's own wheel hub motors to help not only drive the beast but also to help stop and store the increased regen energy (much heaver load).
Maybe this is how electric trucks in the future will be configured. Instead of hauling a 10 foot bed around with you everyday for the 2 pieces of paneling you carry in a year you could just have this third wheel trailer. It's usually sits at your house acting as a solar collector. The trailer's battery is also used for house energy storage. Just thinking out loud...