Jim, have you heard Bruce Robison's chamber over at Premium? Pretty cool sound, but I can't recall what he was micing it with. I sometimes run a feed into the tracking room at 5am (long decay, great drum room) and mic it with whatever omni isn't being used somewhere else (KM83 or Beyer M101 usually). There's almost no absorption in that room so it sounds like a big chamber. I did the same thing at my old place in Driftwood, which had over 3,000 s.f. of tile on the floors. Amazing reverb.