OK, given the choice between mounting free standing speakers on the wall and going with in-walls, I would go with in-walls. The in-walls at least are designed to be in-the wall. M22's are not.

You could check out the on-wall speakers Axiom makes.

Sorry, I have somewhat strong opinions on ceiling/wall speakers (and TV's/fireplaces). I feel if you are going to spend a small fortune on your gear, why handicap your movie experience to make it look 'pretty'.

Dave
Audyssey Setup Guide