Wait for PS Audio's new speaker to come to market. Looks like a serious contender for a large space. "Only" 29K/pair :)
The PS Audio aspen FR30 utilizes four 8-inch cast-frame, aluminum cone woofers with 12- ounce magnets. The woofer’s motor structure features a split-magnetic gap and double Faraday rings for improved linearity and wider bandwidth, and the woofers’ articulate, agile response complements the speed and transparency of the planar-magnetic midrange and high-frequency drivers. The woofers are augmented by four 10-inch side-firing passive radiators, for the authoritative low-frequency extension. The FR30 presents an easy-to-drive load with an 87 dB sensitivity, making it ideal for use with a wide range of amplifiers.