What we really need is the ability to construct a DOOR with key underground, then we just mine a room with a 1 tile gap connecting it to the rest of the cave and install the door, bingo theirs your house dwarf house.
I don't see why a workaround isn't possible. The supports have a radius around them preventing a collapse so long as you mine in that particular area. I'm going to make a bit of a leap here, but it seems reasonable to assume that destroying the support doesn't immediately cause a cave in, so couldn't you use the supports to carve out the area you wished to inhabit, and then destroy them?