Bulk Barn only has oat bran.
According to http://www.cor.ca/en/20061, K2 Milling Ltd (in Tottenham) & Port Royal Mills Ltd (in Aurora) produce oat flour. I just left voice messages with the 2 companies. Hopefully they'll have stores in Toronto, where I could buy 1 or 2 pounds. If they reply, I'll post here.
Do you know which store in Toronto (near Thornhill) sells oat flour?