A week or so ago Jess told me something I never knew about Illinois' built landscape: that many of its homes were built out of plans from a Sears catalog. There's some history about this phenomenon here. Just about anything I present as a fact comes from something linked from there.
I'm just starting to read about this but I already love it. They'd give you the plans free if you ordered all the supplies from Sears, and when you did, two boxcars full of lumber, paint, varnish, nails, and shingles would arrive at the nearest train depot. Then you'd have to find local skilled laborers to perform the parts of building you were unable to do yourself.
I'm trying to think of this through the lens of Christopher Alexander's The Timeless Way of Building. These houses were largely built in the suburbs during the post-World War I housing boom, in the dawn of American car culture. It appears that in some cases a single entity built an entire neighborhood full of these houses at once, but in most cases individual families decided on and supervised construction of the designs. This autonomy could allow for a house built somewhat around the land and the needs of the builder. According to the oldhouseweb link, customization was common and encouraged by Sears, and the houses were often built largely by the homeowners themselves.
Through Alexander's lens, one of the saddest trends in modern housing development seems to be that people mostly don't build or even help design their own houses anymore. Specialized architects plan entire subdivisions and people are left with a small set of generic models. A builder of a Sears Catalog house, though choosing from a catalog, had hundreds of designs to choose from and an infinite array of possible customizations. The houses were built one-at-a-time on land owned by each home owner, allowing neighborhoods to form, and for houses to rise and decay and crumble in their own time. I don't think I'd call the Sears Catalog a "pattern language" exactly, but it seems a lot closer to that than anything being done today (also, you should not pay attention to what I call things because I don't really know anything).
So you can count me as fascinated. I think I can get this book about Sears houses through ILL here, so I'll give that a shot once I'm done with the two books I'm working through currently. Woot.