Yuk. I'd go smaller, use subwoofers, and do a 7.1 system. I'd never go back to 5.1. Assuming this is a mainly HT setup, you have the room (room for speaker placement, you don't need room to go 7.1) and are going 7.1, put all the all matching speakers at the same ear level. LCR close to the display and subs at different ends of the room.
At the 800 Diamond cost level I'd look elsewhere, but hey, you're the Boss.
At the 800 Diamond cost level I'd look elsewhere, but hey, you're the Boss.