My M22s are currently sitting (not connected) atop of the right and left oak towers of my entertainment center.
Have you considered using the M22's at the front of the stand (just move them forward) for your height channels?
Using the M22s will be a consideration. In fact I was thinking that once I upgrade my AVR, I would place the M22s toward the front edge of the oak entertainment towers until which time I purchase another pair of QS8s. I would then work to fashion a matching oak mount which could protrude out from the front of the oak towers 1-2 feet.
Epic 60 - 350 7.1
Mitsubishi L75A91 75" "LaserVue"