I was reading a book about Tarot Cards and was surprised to learn that hair colour plays a bit of a role in Tarot readings.
The Minor Arcana cards have four suits - Wands, Cups, Swords and Pentacles, corresponding to the Clubs, Hearts, Spades and Diamonds in a normal deck of cards. Also like a standard deck each suit contains cards numbering one (ace) to ten, then subsequent cards representing people. The slight difference being that the Tarot have an extra one - King, Queen, Knight and Page as oppose to just King, Queen and Jack.
Apparently these characters are represented differently for each suit - the Wands are ruddy, red-haired and hazel/blue eyed. The Cups fair, blond and blue-eyed. The Swords apparently fair, dark-haired and dark-eyed. And the Pentacles swarthy, dark-haired and dark-eyed. Hence the "you will meet a tall dark stranger" patois.
The book didn't illuminate on how old this tradition is - understandably so given how murky and interesting the history of the Tarot is in general. An on-line search was likewise unfruitful. However, on the Wikipedia page it states that the suits equate to different social classes. Wands = peasantry, Cups = clergy, Swords = nobility and Pentacles = Merchants.
So going by that the redheads would be the common folk I guess.