I would really like to see this, a machine that uses extruded concrete to construct walls guided only by computer renderings. The creator, Prof. Behrokh Khoshnevis of USC, claims that further refinements will be able to place reinforcements, wiring and plumbing lines, and simulate insulation. With all of those components, it would be conceivable to build an entire habitable structure, less doors, windows, appliances, and other non-structural accutrements.
It is the step of non-concrete wall elements that will be the true test. At this point, I am unable to see how an extruded form would be controllable enough for rebar and wires. Living here in Southern California, aka Shakeytown, the rebar is of particular concern. I doubt that it will be accomplished very soon, but I am more than willing to be proven wrong on this one.