Vendor list from last year, from memory, not all-inclusive by any means.
Key, OST, Rails Unlimited, Caboose Stop Hobbies, P&D, Des Plaines, Kohs, Sunset/3rd Rail, Baldwin Forge, Altoona Model Works, Bill Davis/American Scale Models, Midwestern Model Works, O Scale Resource, Union Station Products, Atlas, Mike Deberg, Protocraft, Keil-Line, Right-of-Way, Hill Hobbies, Mullet River, Berkshire Valley, Rich Yoder......
Unknown vendors include somebody selling Marcway turnouts, a book and photo vendor, the guy that does the CNW passenger cars, and several others I can't think of at the moment.
Glenn with Mullet River retired, Lou Cross with Right-of-Way passed recently, the owners of Berkshire Valley retired, and John Keil with Keil-Line passed away. I know Right-of-Way will continue on, but won't be at this show due to required California legal terms when transferring the company. Somebody bought Berkshire Valley, but I don't know if they will be at the show. Glenn Guerra will likely be with O Scale Resource, but I don't know if he will have any Mullet River product with him (or if he even has any left).