Reconfigurable House

If we didn't have plumbing, electricity, or communication devices, houses would be pretty simple. In fact, before those things, houses were. Four walls and a roof to keep the rain out. Floors came later.
So, I remember hearing on some TV show or other, probably either the science channel or the home improvement channel, that someone invented pre-fab walls that contain electric wire and pipes, and can be reasonably reconfigured. Throw together an arbitrary arrangement of walls and at least 99% of the time, the electrical wires, pipes, and telephone cables would all properly connect to each other. Admittedly there are some extremely bad problems if they don't. They did this so that one could just buy a bunch of these walls, slap them up over a cement slab, and call it a house. This saves a whole bunch of time. Especially all that window-fitting, plumbing, electrician time....
Housing is pretty strange worldwide, and even today in 2010, there are people living in straw huts. (Mostly because this is all they can afford.) Charities aim to change this, and with this system, they don't have to ship over a building team. Just a bunch of walls.
In fact, I remember one technology taking it further, and requiring only a bicycle-sized machine, a bag of cement-ish stuff, and the local dirt. This made cinderblock-like bricks by the metric ton, which was soft at first (and thus could be fit with pipes and whatnot), but hardened after a day to granite-like hardness. The machine cost $1000, a bag of the quasi-cement was $20, and together with a $30 shovel could build about three houses. $5000 would build an entire village, and between the 30 or so families that live in it, they could definitely scrape that much together on their own.
Whatever helps us live better, I'm all for it. Also, I have the strangest feeling of deja-vu about this post, like I wrote it before.