Panther Run Saddlery is probably closest, though you can contact Kate Wilson at Dutchess Bridle and Saddle and see what she has. You may want to consider a Thorowgood high-wither model (the T8 is about $895 new) – Kate carries those. They’re synthetic, have conformation-specific features for the high withered horses, and offer a flocked panel and changeable gullet (way nicer than the Wintecs in quality and fit IMO). Kate also might have something used. You can also contact Annette Gavin at Hastilow USA – she also carries the Thorowgoods, and has some used saddles as well. Good luck!
"It's saddle fitting - not rocket science."