This house is built by a company called BlueSky MOD. Their motto is "Retreat without a footprint." They are meant to be vacation homes but I think they work just fine as a small year-round home. Who needs a big freaking mansion anyway?@$%? Anyway, there are a lot of good eco-friendly things about these homes; they can come with composting toilets, solar panels, cedar siding (never needs painting/staining), low voltage halogen lights, straw-composite interior walls, etc. They do not need huge machinery to be assembled so they cause less damage to the land. I've seen somewhere, i don't remember where; some houses built on some kind of high stilts, so that the only damage to the land other than footprints from everyday walking would be the four stilts in each corner.
Then there's these homes, called weeHouses, that start with a basic model, prefabricated and delivered, then if you need a second floor or a guest room later on, you can order another prefabricated modular unit. They're cheap but not as friendly.