Your going to find that whatever Master Cylinder you use it will need a custom bracket. You may be able to adapt a bracket from a smaller series Truck. The larger Trucks don't have a lot of aftermarket part available.
For my project I started with a generic pedal bracket, it allowed me to position the pedal correctly. I had to Fab up a support bracket for the Hydrobooster. All of this is located under the floor, I have enough clearance to service the unit. The Hydrobooster on my Truck came from a 1990 GM Motorhome, it had 4 wheel disc brakes. The Master Cylinder is large enough to handle the volume required. Do some research, check out NAPA or RockAuto, you should be able to find something to fit you needs.
