I Hope this thread becomes a "How To" for the next person with this question. What I am trying to achieve is to install a 50" plasma and C, L, R speaker on the wall and completely hide all cables with no comprimise. My speakers are B&W FPMs on wall speakers and mount similar to the way a plasma would. I need to hide the following cables: Power cable, HDMI (1), speaker cable for each speaker. Here is my idea and some pictures...any help and advice would be appreciated and needed :o

The first idea which came to mind is to carve out the concrete between two bricks put the cables there and run to my av cabinet (they only need to reach the rear of the cabinet). Then put concrete back over top of the cables. Possible? My two concerns doing this are will the conrete eventually eat through the cables, and since the concrete is over 100 years old will filling in new concrete stand out to much?

This pic shows how I currently have it on an arm. You can see the AV cabinet to the left and the cables are now runing through a aluminum cable cover, and the speakers are on stands.
http://i98.photobucket.com/albums/l269/vancouver_03/HPIM1576.jpg

another angel of cable cover
http://i98.photobucket.com/albums/l269/vancouver_03/HPIM1577.jpg

close up of brick
http://i98.photobucket.com/albums/l269/vancouver_03/HPIM1575.jpg