One source for scale model disc brakes is Ebay. You can get actual metal discs and rotors for RC cars which are usually 1/10 scale. Check them out we just used these on a scale model we built for Toyota and they came out killer, I did buy two different sets and combined them to make what you see. I also machined some special hats to fit the parts. Check it out you will be amazed
What you are looking at is a billet alum scale wheel for a Lexus concept car that is being shown on the Auto show circuit and this is the scale model with a almost identical disc brakes as the actual car.