I've been taking some measurements and pondering how to run wire, mount speakers and so forth.....

I think I can get M3 wall mounts for the surrounds and back channels. I'll have to anchor them to the walls better than just using the supplied brackets, but that's not a problem.

For the ceiling speakers, I'm leaning towards two sets of in-wall M3's. They are the shallowest option. I will build some cabinets that I can recess them into, then mount the cabinets to the ceiling above the seating area. The ceiling height over the seat is 8.5'. The trayed perimeter is 7.5'. That gives me 12" to work with for the ceiling speaker cabinets. The in-walls are roughly 3" deep, so I'm pretty sure I can angle the cabinets plenty. I can build these ceiling cabinets at any angle I need to get the speakers to fire at the MLP. I only have the single row of three seats anyway.

I'll have to run the wires surface mounted, but I can figure out a way to hide them behind some decorative trim.

Thanks for all the input. It's been very helpful.