For the OB thing, my current thoughts are to go with the PE IB driver: 14 mm Xmax, Qts 0.65. Sensitivity is kind of low at 88dB, which is bothersome. I'll be looking at this for a while yet.

The problem with somethign along the line of IB is that there's little wall space to be utilized - very open floorplan. And the other problem is that the walls would probably rattle to beat all. Cathedral ceiling, 15 ft at the center. It's slab construction, so the walls aren't doing too much bearing other than self weight - it think they'd really be annoying.