I found a very cheap set of large heavy pieces online. However, the board that I have is too small for them. Instead of buying a new board for $100+ I decided to make on from scratch (relatively).

Used:
Plywood for top playing surface, cut into two (for folds)
1.5"x.5" wood for inner walls (with 4 degree cuts for the connection between them)
Hinges to connect the two halves together.
and cabinet magnets to keep it shut.

I sanded, painted, and am almost finished.
Will post photos and more information later.