Rolling Thunder stole my thunder. You need to erect a base that you can mount your bracket to. Use the 2x4, and possibly a 1x12 to get the base you need to screw the bracket into. This will due you fine. Also, buy one of these.
All you need is one of these below. They're $119.00 and Wal Mart carries them. The link below has them on sale for $69.99. I've hung two and I'm no carpenter. Find the studs and pre-drill three holes, very easy. It tilts up and down, side-to-side. If you ever rearrange your LR that feature may come in handy. B&H Shopping Cart | B&H Photo Video
Buy your mounts from HDMI Cable, Home Theater Accessories, HDMI Products, Cables, Adapters, Video/Audio Switch, Networking, USB, Firewire, Printer Toner, and more! High quality and very inexpensive!
dang, I wish the forum wouldn't do that that to links Wall mounts at monoprice are very high quality and most are less than 20 bucks.
Well, Christmas completed the room. I gotta get some pics posted, but I opted for an entertainment center instead. Kinda took tirk's original idea. But like I said, I'm gonna get some pics up later.