rotipom,
I am using the M60's in a room that has a sloped roof going from 10' down to 8' with no issues. I am only able to pull them out from the rear wall approximately 18" (or less)...I know they would sound better with more "breathing room".
I would be mindful of the need of the speakers to breathe as you build your clothes closet. You don't want to get used to listening to the M60's with the current room behind them and then block off the back of the room and possibly have the dispersion change. Also, a bit of distance from the side walls allows them to breathe better and sound better too.
Hope this helps,
WhatFurrer
