Luckily I was able to disguise the existing niche (formerly an unused opening into the dining room) and run speaker wire and electrical cords through it with a false beadboard front that matches details found elsewhere in the room. The bracket for the tv was then mounted to this front. The lower 4 shelves on the right hand side were able to be deep enough to house the equipment while the rest of the built-in appears to be a standard 11" bookshelf. I think the drawing above helps explain what I came up with. I didn't put any doors on the lower half so that these shelves could be their full depth. Plus one could use remotes on the equipment without having to constantly open and close doors to access them.
Finding a good contractor to build the piece was the next step. After pricing the drawing through a few talented finish carpenters, I went with Jozsa Woodworks out of Woodbridge, VA who I know through my work. They were a joy to deal with!
The day of installation was exciting. The crew of 3 plus an electrician showed up right on time (impressive and something you don't always find in this line of work) and began to make sure the pre-built pieces fit exactly and prep the wall for installation. They spent hours making sure that the piece fit in perfectly and their attention to detail was astounding. I could go on and on, can you tell I was impressed?!
Please excuse the bad photos from my iphone!