US ebay will have plenty, prepainted too. Also give BigPhil@ESR a shout and see if he can price match.
Since getting my new wheels I'm contemplating these while I save up for some Nismo skirts as I have seen a few more stone chips (wider wheels, who'd have em!). Any one have any ideas if they Nismo skirts give anything like the protection of the splash guards, or at least more than the standard skirts?