I have never seen any models except the 221 and the 621 / 622. I'm guessing there just isn't enough demand for something that would likely be priced in the $5k to $6k range. For that kind of money you might be able to get a used pro model, although it may need some work. Have you looked at the Kessler Custom models? They are priced close to a student model, but have mostly great reviews. If I were to get serious about doing pit work, I would think hard about getting the Kessler low C for $2,249.
What saxhound sez about Kessler. And we have some very nice Leblanc pro bass clarinets for around $3000 at Quinn the Eskimo Brass and Winds. Full disclosure, QTEBW is a forum sponsor and I work for them. Good luck!