Yesterday I listened to an episode from Red Ice Radio titled Bodhidharma: The Blue-Eyed, Red-Bearded Barbarian. I won't link to it as I felt it had mildly racist undertones that I feel uncomfortable promoting without comment, but it contained some interesting information regarding red hair, and it's there on YouTube for anyone that wants to search for it.
The main thrust of the interview was that Bodhidharma, the famed Buddhist monk, was a red-haired, blue-eyed European. He's apparently described as 'blue-eyed' and 'red-bearded' in ancient texts, and also depictions of him in art show him as a red-bearded European.
(Incidentally, the names Bodhidharma and Buddhist look quite similar to me.)
Apparently, a lot of people were referred to as 'red-bearded' in eastern texts, the Chinese regarding all foreigners as red-haired barbarians. This seems like something worth delving into more. I've never really looked very deeply into red hair in the east, so I might have to widen my net a bit and start searching.
The guy being interviewed also stated that the native-American Mayans put on fake red beards to signify their nobility.