I was lucky enough to see the Harry Potter Exhibition over the weekend, and it truly was amazing. I hate the movies and have stopped watching them in the theater, but the exhibit was still worth it.
They had a Rook and a Pawn on display, but no photography was allowed. They had a Knight in the lobby of the Museum of Science, so I did get a picture of that.
For sale at the OMFG Expensive Gift Shop was both the Wizarding Chess Set, and a Quidditch Chess Set. But WOW, were they OMFG expensive.
The Quidditch set had interchangeable pawns so you can play as your house of choice. It is the more affordable of the two, and they are both of excellent quality, but man I could never see myself shelling out for one of them.