Starting to put together a plan for smaller rear brakes. Goal is to match the bias of Blaine's 17" kit, raise the calipers up out of the way. I'd also like to retain a parking brake and add some width to the rear axle once the calipers are less exposed.
Stock super duty rotors are 30mm thick. I had no luck finding a smaller caliper to fit my current rotors. After far too long looking at brake parts, I think a rotor from a 2000-2011 Cadillac limo could be modified to work. This gets be down to a 20mm rotor and the parking brake hat is only 5mm bigger. Down side is 8x6.5 and the hub register is too small.
20mm rotor will allow use of a rear caliper from a trailblazer, which is a single 48mm piston versus my current dual 44mm.