This is the BrightBuilt Barn, a super-sustainable prefab structure that is being used as a sort of outbuilding but could easily be adapted into a home. It is insanely efficient, and when your carbon footprint is zero, LED's around the house glow green (they are red if you are getting into a dangerous energy usage zone). Another interesting thing is the use of open-source collaboration in its design. The whole thing, including the timber frame,roof, siding, insulation and finishing comes all under $200,000 US. Plumbing, electrical, heating and the solar stuff costs extra and of course you would need a foundation and excavation, but I think its still reasonably priced (especially around here where you still can't find any house for under $350,000 Can). Someone is finally making some significant solutions in housing.