Check out Roadtrek's new RV based on the Sprinter Van, then do a little research on the WEB and see that they are producing Hybrid Sprinters for the European market. Hopfully these will get to the US soon. Throw some solar panels on the roof and you have a Tri-brid, also check out air-x, so if it's not sunny out you can capture the power of the wind. Let me know if anyone is doing this. I'm planning on hitting the road full time in a few years and doing my research now.