Thanks to Nick Hardman for pointing out this site in the forum. Contour Crafting is working on some interesting machines that will someday automate home buildings. See some video simulations here.

“Q:What will the buildings cost?

A:If you were to have your clothes, shoes, or cars made manually you would have to pay 4-5 times more. These products are available at the current prices because they are made automatically. Our houses are now made manually. If automated by CC we expect the cost of construction to drop to 1/5-1/4 of current cost.

A:There will be several variations of the machine to suit the needs for emergency housing, low income housing, single residence detached
housing, multi unit structures, condominium complexes, public buildings (schools, hospitals, etc.), and high rise structures. The machine will cost between $500K to $700K for average size (2000 sq ft — 200 m2) detached houses. This is not much given that a concrete pump truck is now $300k-$400K. Note that with one machine numerous homes can be built.”