Here's another trick to consider. If you know that you have safe framing at either end of the wall, and assuming there's a door in it so it's not too long of a wall, you can run an attractive piece of stained wood as a stringer across the wall surface at one or two locations with a vertical separation. For example if you know there is safe framing at either and you could screw a 1x4 (or whatever dimension you need for the required stability and weight distribution of the TV) at both ends and then attach your TV mount to that. You could also use a 3/4" Baltic birch plywood, which we would expect to have greater stability, and frame and stain it to match the cabinetry in your rig.
