It's interesting. WhatsBestForum, founded by Steve Williams.
Here he describes the creation of his new music room in Southern California. Leaving behind a cavernous "dream" listening room in the Bay Area, Steve loves his new house and planned community in his cherished Souther California, but finds he can't build an outdoor building for his new music room. So he builds a music room inside the existing house, by taking the top of a living room with 20 foot high ceilings. The resulting room is small by the living large standards you might expect him to have (guy with megabuck system, megabuck house, etc) but Steve puts so much effort into refining the acoustics (with hired professionals) he finds the result even better than his last room which would be a dream for just about any audiophile.
The thing I like is this: it's only about 50% or so larger than my puny living room. So there is hope!
(When there is money, there is always hope.)
More serious and more informative that Cat's site, though possibly less entertaining.