Welcome to the Busse forum.
There are several good sheath makers out there that do an excellent job on the bigger Busse's.
Buy Brown
Normark
On scene
Survival sheath Systems
Kenny Rowe
I don't have their emails, but if you check back I'm sure some one will post some of them.
You also might want to try a search for sheaths here on the Busse forum, that subject just came up not to long ago.
Someone had a large knife and came to us because they knew we did a lot of sheaths for the BM's.
Let us know what you find, I'm going to need one for a 19" custom soon.
Good Luck......