I've done timber-framed houses with those foam panel walls. The GC showed us neat trick (he of course had done many more than we had). We used a gem box (old work) cut into the plywood. Then take a torch to a plumb bob and drop it down the wall. It would melt it's way right down the wall. Not sure what kind of fumes we were exposing ourselves to.
But to CRW's question: No haven't heard of that construction before. The only thing that sounds like a pain to me is learning a new technique, otherwise its all work no matter how you do it. (its all a pain). Just like the rope guys cringe at the thought of new homes in EMT. It's all I've ever done, and once you get the routine down, it's not that hard.
