This fits so perfectly into the space, I have a sneaking suspicion it was custom made. I have seen some very lovely bulletin boards that are similar at Ballard Designs:

http://www.ballarddesigns.com/bd/11713

I think Ballard as well, there are several outlets too. You could also get a really large frame. Some craft stores have empty frames for sale, even that big. A large garage sale painting or a clearance item like a mirror would work too. Get a large sheet of homasote (pressed paper sound proofing board) at Lowes. It's around $10 for a 4x8 sheet. You can cut it with a razor. Cut it to fit the frame and cover with fabric. Staple the fabric on from the back. Add the decorative trim nails from the front. You can also skip the frame and add the tri m nails or ribbon on the edging. It is very light and you can mount it straight to the wall. This one looks like burlap (often stinky). A fabric with a looser weave won't show pin holes. I have some in a green silk burlap I found in clearance. For others I use the large painters canvases. For the board and canvas to cover, you can do a 4x8 board for around $20-25.

There's a great company that makes them Massiv Brand, I've seen them in a few stores.