My only suggestion would be to check ebay and see if anything pops up. If something does and it is cheap most likely (not always, but most of the time) the saddle isn't of the greatest quality but it might do the job for the time being. Although I have never heard of a western saddle over 18" or 18.5" they could be out there. If you are willing to spend the money I would look at a custom saddlery, that way you get the right fit for you and your horse, plus it would be of better quality. Hope this helps, defiantely check ebay never know what you'll find.