Ok so here are some parts I have recieved of late.
These are the Hubs and spindles that will replace the broken ones. They are larger and will take much more abuse. They are trailer hubs with a 4 on 4 bolt pattern to fit our wheels. The miata rotors should slip right on to them as well. Then we just have to make a kingpin bracket to hold the caliper and attatch to the A-arms. I think I will add a zerk grease fitting so we can lube them without getting too dirty.
These are the master cylinders. The one on the left is the brake cylinder and is 7/8 of and inch bore. This pushes the brake fluid to the two front Miata calipers and the single CB750 rotor in the rear. It should have a much better brake feel than the small Master Cylinder of the motorcycle (mounted upside down...oops :) ) on the rear rotor only. The one on the right is 3/4 inch for the clutch. This replaces the clutch cable to the engine. More on that later. These will be attatched with 3/16 inch hard brake line to the calipers.