I recon anyone considering a HT build and the sub or subs will work good on the front wall. Build a folded horn along the front wall, place the F L and R speakers on the top. Plenty strong enough even for heavyweight active speakers. A lightweight frame for an AT screen and your done.... Not a speaker in sight. A mate told me if he had $20k worth of speakers he would want to look at them, but you really just want to listen to them.
A bit of a story to the cables. The Mk 1 HT had a 100" 4:3 screen with speakers on either side. To the right of the right speaker is a brick wall, a fire place in the other room. The speaker cables went through the corner of the brickwork, which I covered with gyprock.
Then the Mk2 reno to get a bigger scope AT screen so I moved the screen forward 600mm and the right of the screen is in front of the brickwork but I still managed to hide the cables. But when the active Seaton Catalysts arrived the cables have XLR plugs on them, a bit big to get though the conduit if I took them up into the roof and down in side the wall. I had run 2 lengths in the wall but they got filled up, 4 more runs of cable when I went 7.1 and front hights, that I'm not using. When at building stage you want conduit every where. Then I used speakon cables with plugs attached for the horn subs hence the 5 cables, but....
the plan is when I finish making 2 screen masks for 16:9 content, they will hang on the side walls when not in use. Then underneath will be 2 more false grills which will hide the cables. All the black works well above and either side of the screen.