Early in his career, Frank Lloyd Wright developed several detailed proposals for low-cost prefabricated houses sold through car dealerships. It was said that he produced more drawings for this project than any other. The project however was one more casualty of the First World War, with just one prototype constructed, in Milwaukee, Wisconsin [but see below]:
He revisited the idea of affordability through prefabrication in two 1950s collaborations with Marshal Erdman, a small flat-roofed mezzanine house, which he called a “one-room house,” and a low spreading ‘ranch house’ type.
Both, he said, were intended to “immediately catch the eye” – using the machine to make attractive housing affordable (just as he talked about in a 1901 speech). “Alongside prefabrication managed by Erdman's company, the architect sourced off-the-rack Andersen windows and Pella doors and used basic materials like plywood and Masonite to cut costs.”
[Pics from and more stories at Dwell, Wright Library, Life at 55mph, Save Wright, Austin Cubed, Live Modern, Architecture Theory.Net. Floor plans are adapted from William Allin Storrer's excellent book The Frank Lloyd Wright Companion, and appear by permission.]
CORRECTION: Commenters point out, correctly, that while “only one [flat-roofed] example of the [early] Richards B-1 Cottage shown above was built,” there were “four hipped-roofed examples [built]), two in Illinois and two in Wisconsin.”
And “it was far from being … the only pre-fab built. Several other types (including the duplex seen in the background of the above photo) were erected from Gary, Indiana, to Monona, Iowa. There are images of the interior of the cottage, which has been restored and opened to the public. Articles have been posted online. It's small, but charming.”