Re: sliding barn door hardware (interior)
Try Richards Wilcox. I think they're still in Mississauga. They are a garage door manufacturer and I seem to recall this (or very similar) hardware being used on their sliding fire doors. That hardware was very common about 50 years ago.
Maybe try some of the industrial door service companies in your area. They may be able to order it or at least point you in the right direction. I wouldn't expect to get it for less than $300 but that a lot better than 900.
J.P. Rap Mount Hope Ont.
Carpe Ductum (Seize The Tape)
"In this world, you must be oh so smart, or oh so pleasant." Well, for years I was smart. I recommend pleasant. Elwood P. Dowd