The speaker would be at least 7 feet from the rear wall, which has a closet, so it would still higher than I'd like. I want it retractable b/c I have 18' ceilings with 10 ft tall 6' wide windows along the one wall, and want to maintain the open, airy feeling when not using the speaker.
Using a stand and simply moving it out of the way is a consideration, but not elegant for the amount of money I'm putting into my entertainment setup, plus it's still in the way when in use. The ceiling solution would allow people unrestricted motion in the room even while in use. That area would be a high traffic area with more than a few people over.
As for the potential for movement while in use... I don't see this as an issue, especially since the Q8's mids are on the top and bottom.