American science and surplus has some very wide duct tape.
Wider than some ducts, in fact. For really big fixes, this is the "Big Fix Duct Tape" from NashuaÂ® Tape. You get a 15-foot roll of 12" wide tape in the classic silver color. You cut it to size and shape for custom repairs to plumbing, HVAC, sporting goods, furniture, doors, windows, tarps, and car and truck bodies, for starters. Make cuts on the side with the paper liner. (The liner's also there to keep it from sticking to itself and making you look like you're in an I Love Lucy episode when you apply it.)
39757 BIG FIX DUCT TAPE