It may be a special order item. K.B. Canham Cameras takes special orders for all sorts of Kodak films at all sorts of sizes, you might check there: http://www.canhamcameras.com/

There's normally a minimum order and he does group purchases on such things.

I know for a fact he recently sold out an order of 8x10 TX, if you don't want to buy the minimum you might check in on when he plans to do another group buy.