Here ya go Kitten Val. A lot of places only sell full seat sizes, but if you look around they are out there. Smithbrothers sells 1/2 sizes for example David Motes Roping Saddle by Saddlesmith - Smith Brothers
Teskeys Teskey's Saddle Shop: Saddles, not EVERY new saddle here comes in 1/2 sizes but the majority do.
Just a couple places, I don't feel like checking every store haha.