I use Aerodynamic Plating in Gardena, CA. They are about the best around and can color match if you provide a sample. Their min. charge is around $70 though. I have never anodized r/c parts (we make lots of aluminum parts for NHRA drag race cars) so I don't know what alloy they are using in r/c. Also note that the parts would have to be stripped and prepped for anodize (polished or glass bead blasted) which would add to the price. I have seen home kits for anodize for home use, but have not seen any parts produced by them to see if it does a good job.
hope this helps
Steve