Hi Graham,
I did get a sample from a powder coat firm in Warrington last year, before I got my car. The match was very good to the roll hoops. I was told at Lifes that the bracket bushes would no longer fit if the rack and brackets were powder coated and would need some filing work. There was a risk of getting a rattle if too much of the bush was removed...so I didn't bother.
I did see a black rack at Thrill on the Hill, but the bush looked to have been replaced with a rubber grommet

Will keep my silver set up for now I think..