Michael Jantzen is best known for his M-House and his other transformer houses that have been everywhere on the net, but on his website is a link to some of his older projects, from the seventies, and he did amazing work.
In an interview on his greenhouses and building technologies, he describes how he used cheap and basic agricultural components to build a lovely little solar vacation house, shown here. He writes:
"The Solar Vacation House was primarily made from agricultural components, which included a half of a grain silo roof, and corrugated metal siding. The structure was passively solar heated through south facing plastic bubble windows, a sliding glass door, and a large translucent fiberglass sloping roof."
Image Credit: Michael Jantzen