Joined: Sep 2015
Posts: 1,300
Likes: 210
From: Ottawa, Ontario, Canada
Bikes: TrueNorth CX bike, 88 Bianchi Strada (currently Sturmey'd), Yess World Cup race BMX, Pure Cruiser race BMX, RSD Mayor v3 Fatbike
Try nashbar.com cyclocross frame.
Are you willing to buy a used frame? Either Kijiji or the Pinkbike buy/sell seems to have stuff that fits that, at least near Ottawa.
Why the requirement for disc?