I found this online.... appears the company still is in existence but has now merged... Maybe searching for a slightly different name will help you... SIMCO/LONGHORN SADDLES
In October, 1990, two equestrian companies merged, enabling improved operating efficiency for both companies and better service for you, the customer. The companies, formerly known as Simco & Longhorn are now Simco-Longhorn Co., Inc. Offering a great saddle selection at an affordable price.
The Simco plant consists of 130,000 square feet. It remains in Chattanooga, TN and will continue to make quality Simco products including saddles, strap goods and other equestrian items. Simco products have been recognized as world leaders since 1933.
The Longhorn Leather plant remains in Greenville, Texas where only the best roping, cutting, show, pleasure saddles, and strap goods are handcrafted. We will continue to make the always popular Longhorn and Billy Cook Saddlery labels in Greenville, Texas. Longhorn handcrafted saddles have been the favorite of thousands since 1913.
Simco-Longhorn Company, Inc.