VERY common in New Mexico and SE Colorado. Several farmers around me have adobe structures on their land. They're pretty bad ass structures. The farmer who hosts my churches annual skeet shooting event has a small campground on his property, and the lodges are all made of adobe. Very sturdy, and cool in the summer. I have no idea what building codes are involved with them, or how you'd handle plumbing and electrical, but from the strict standpoint of a building made of it, I would build a house out of one where I live in a heartbeat with it.