Got a response back from RB. They gave me a link to the rotors with an option to add pads.
https://racingbrake.com/one-piece-ro.../rl/nis-irk-02
So $2K for both F/R direct from them. I'll probably grab the fronts somewhere else and hold off on the rears for now. The hats are currently backordered - they said 'in transit 2-3 weeks'