Enjoyed playing this game when we were in the US this year.
Mayfair have a photo of one on their website, but they also have a photo of a Rocky Backglass but it is not in stock. Apart from the usual suppliers and posting wanted ads everywhere, might be worth contacting SS Billiards
http://www.ssbilliards.com/sale.html if they have or can source one.
Good luck with your hunt.
