Flat Screen Television behind speakers

I like the idea of theatrical stage curtains in front of the TV that can be opened and closed with a remote. The sound bouncing off the screen won't come directly back toward you but will glance sideways, hit the side walls, and then make it to you ears. Absorption can be placed on those side wall early reflection points, or in the path between the speakers and the screen to acoustically shadow the screen from being directly hit with sound from the speakers. Front to back room reflections might also be a problem and that can be dealt with by adding diffusion and absorption to the back wall. 

I have a similar sized TV but mine sits off to the right as I face the speakers (room is multi-purpose). When I listen to the 2-channel, I place a sheet over the TV to stop reflections and at the same time not absorb, I don't need that.

I tried different varieties of coverings (sheet, blanket, comforter) and the sheet was the best solution for me.

In my 2nd system (living room) the reflections off the tv and coffee table were noticeable. For listening sessions I would put a blanket over the tv and move the coffee table off to the side. I'm not like some of the guys here that can hear a gnat take a crap on a piece of sand paper because they switched to a different brand of ethernet cable. But covering the tv and coffee table made a noticeable difference.

I would place the speakers roughly the same distance apart as they are from your sitting position. Some people like to be inside the triangle, other outside of it. If I had $12k speakers I would want to squeeze every ounce of performance I could from them It's shame they have to go flat against the back wall. 

My condolences on the compromises you have had to make. With speaker placement as well as the TV. 
 

I would go for the “dust cover”… make it absorbent. I use a very heavy tightly woven wool carpet behind my speakers (see my UserID). Makes a big difference as did getting the equipment racks out.

If I was confronted with this compromise, if I had a study or smaller room I would get room appropriate sized speakers and build my system with higher quality (but lower power) equipment. If carefully built the sound quality could far exceed a larger system in a compromised setting. 

Yep, I have a quilt on mine. Pull it off when we want to watch a movie and back on when I want to listen to music.

All the best.