We've been watching the prefab scene as close as anyone, and it seems the recreational variety is honestly taking hold. This company, Cottage in a Day, provides factory-built, energy-efficient, green homes. They currently provide roughly four models, which, not counting the included decks, range in size from 182 – 375 square feet or more. The homes are made in Traverse City, Michigan and built with locally sourced materials (except the bamboo). And the idea is that they can be put up quite quickly, assuming the concrete pier foundation is ready to go.