Body art in the workplace

The OC Register has this article on piercings/tatoos in the workplace. It's interesting in that it shows that in Orange County's tightening labor market that less employers care, while some worry about perception even still.

Question: would discriminating against someone who has a tatoo be illegal, if, say, that person was Polynesian? (The recent Ninth Circuit ruling made it clear that certain appearance requirements are ok, but what about when it's cultural?)