John,
Here in Boonton, NJ there were a bunch of houses who had this "new fangled" wiring system in the late '60's I believe. It was a great idea, because you could control so much from any spot. However you can't beat the new systems and the computer wiring that the high end homes now have. The worst part about the low volt wiring in those old homes was that you had to remove the relay through the box and hope that the LV wiring comes through the KO. If you lose the wire, you might have to open up the ceiling to find the end of the LV wire from the switch.
