I have thought of doing this myself and recall seeing a few folks post pictures of their painted guards. The chipping part concerned me so thanks for mentioning that. To counteract this, I considered using a transparant, plastic film on the tire side to deflect the rock, dirt, etc. damage that would contribute to the flaking. In the end, I decided they look good black and match the other black ascents on the car.I painted them on my sedan. Since I am lower, after a day, the paint started chipping.
Thanks for the clarification. One of the examples I saw had the entire guard painted, so I thought that is what you meant. Your (clarified) way sounds much better!