When this gets asked in the Trombone forum, many will point to Doug Elliott, who before becoming a foremost expert on embouchure's as well as a custom modular mouthpiece maker, was a professional trombone player in the Airmen of Note. He won that position playing on a Yamaha "student" model YSL-354. I will also point out that many of the instrument models that were considered "top of the line pro" are now almost considered student horns in some areas.
Sterling / Perantucci 1065HGS Euphonium, 1952 B&H Imperial Eb Tuba, and a bunch of trombones.