Here's a spiffy 10 square meter house from our friends in the Great White North, the Bunkie. It's designed to be put most anywhere without a building permit.
Like any good prefabricated home, it is built to high tolerances in the factory, and screws together quickly onsite. They are pricey but they are also high-spec.
I like its design; it seems exactly what the the 5-year old child of a modern architect might draw!