Try the POR-20 silver, hi temp paint. This brush-on paint will dry in 4-5 hours, and look like you spray painted them. You could paint directly over the rust, or wire brush/sand blast them before applying. I would avoid sand blasting the smooth rotor surface. You can buy it by the pint or quart; it can expensive in larger containers, but its worth it. I've had good success with this product after finding it at swap meets.
