I have a 50" Panasonic Plasma that I am planning on wall mounting. The problem is that my house has a built in media nook that is built for a 4:3 TV (about 40" wide opening).

My plan is to build a rectangle frame made of 2x4's roughly 24"x40"x24", and anchor the back and bottom the the media nook studs, then mount the plasma on the front of the frame so that it crosses over the bottom part of the opening.

Then I am going to place a board over the top to put all my components.

Does anyone have a suggestion on the strongest way to build the rectangle frame in terms of the 2x4s? I am pretty good at building things but I want to be sure to build a strong frame that I can easily remove when we move.

Here is a snapshot of the area in question:

http://img69.imageshack.us/img69/9034/img0654xk3.jpg

I'm not sure I can explain via a forum post how I would build this out but I would suggest you consider finding a way to mount 3/4" plywood to the frame you build - paint it black - and then mount your flat panel mounting hardware to that. There are many different ways to construct what you are trying to do and giving you a clear answer without seeing whats behind and below the tv is petty hard. You might also considering hitting the library and having a look at some framing and construction books for a good strong box frame design.