Did you ever get your TV situation managed? How about a false wall, through which your cords could be run? Paint it the same color as the wall and hang the TV on it. Note: I am a professional organizer, not a contractor, so you would need to see if it's possible to make it secure. Just a thought.

If the drywall is attached to studs (2x4's) then you have to cut out a strip to run wires to put outlets behind television. If drywall is glued to brick then I suggest you build entertainment area beside fireplace for cable boxes and etc. Keep television above fireplace and put mantel directly under television running your cords through mantel to entertainment area and outlets. I am no expert but my DH and I have been mounting our new TVs as we get them and having to address similar concerns.

A good solution to this design dilemma is to make that fireplace pop a little. If you have a small space, I would recommend a gorgeous, cast stone fireplace mantel like this one below.

Wow, that's beautiful!