There are a lot of options out there now to buy a pre made patch board but it is really inexpensive and easy to just make your own from a frame. Mine ended up pretty large at 2' x 4' because I just used a frame I already had but any frame will work as long as it has a cardboard piece inside.
Here is the final result with some of my collection:
To make your own you need:
Any size frame with backing
Any color felt to cover the backing - I got 2 yards from Wal-Mart for under $5
I also used a level as a straight edge and chalk to mark the lines,
Cut the felt a couple inches larger than the backer board to have enough to wrap around the edges.
Then cut the corners off so when the sides are folded over they meet up cleanly.
I started by gluing one edge around the back to hold the felt then turned the board over to glue the front. Roll the felt down to the glued edge and then glue it down a few inches at a time while letting each section set. I used a brick and board to make sure it stayed flat.
After gluing all the back edges down the extra material made the board a little tight to get back into the frame but it fit.
I think it turned out nice and looks great with the patches on it.
I would love to see if anyone else builds one, or has already made one. Send me your pics.