I have long imagined that adapting "metal buildings" now used for barns would fit this niche very well. Add insulation, wiring and plumbing, and an internal facade like sheet rock (or perhaps better) would make it habitable. Perhaps even movable or sliding interior walls that would allow the building to adapt to changing needs such as kids leaving home. And an external facade, nicer than those already used for offices in industrial parks, would make it fit what ever neighborhood desired. A foundation is required otherwise it is just a box waiting to be rolled over (see trailer parks after a tornado).