Here are some updated pictures of my Kyosho ST-RR brushless truggy which I have set up to use front and rear adjustable mech brakes. You have to use a motor spacer to get enough clearence for the brake pads. I am using fiber rotors because they are more compact and you don't have to space the motor out as far. I only had to drill one extra hole in the chassis (for the rear battery tray mount). I am using a TeknoNeu 1515/1Y on 5s lipo, gearing is 15T/50T.
Top view showing the motor spacer and servo
Here is a shot of the fiber brake disc
Shot showing how the spacers allows the brake mounting screw to clear the motor
Shot showing my custom carbon fiber battery tray and aluminum ESC mount