I don't understand upside-down stairs at all. I can understand where they'd make the interior of a roof not so 'lumpy', but the outside of the roof still looks the same.
What we need is a 'double upside-down stair', where the top and the bottom both look like a stair (from the side it kinda looks like a "Z"). That would improve both the interior and exterior of roofs, etc.
Now about the powered circuit thing.
I really like the idea that you don't need a transmitter/receiver to simply use a 'local' pressure plate to open a door (you only need them to transmit power over distances). Course we don't know (and Craig probably hasn't even figured out yet) how far 'local' reaches (will it turn on all the lights in an set area or just the one next to the switch?)
We probably need a separate thread about how this whole "powered circuit" thing will work after Craig works it out, so there's no sense in trying to get into the details yet.
Personally, I'm not a RPG lover/maker so I could care less about transmitters or receivers. As long as a door opens when my little pixel person steps on a pressure plate I'm fine. Not into "lights"- torches work just fine. (But I know the RPGers out there are licking their chops).