Very long, very fascinating article by Margaret O'Connell:
http://www.sequentialtart.com/archive/may04/cv_0504_2.shtml

While it doesn't specifically mention Harudaki, it does shed light on something that had been confusing me: why Katou sometimes appears in the color covers/panels with brown hair instead of blond. Apparently the Japanese really perceive colors differently. To quote:

If, to the Japanese, the distinction that Westerners see between pale brown and yellow hair effectively does not exist, then it is literally possible for a manga character to have what we would call brown hair, but still qualify as a blond by Japanese standards.

It also discusses how blond characters = trouble. Heh.

Tangential note: the article has an extensive discussion on the hair colors of the characters in FAKE (which is how I stumbled across it in the first place), and it explains why Diana looks to me like a brunette in the b/w manga but is described as a blonde, and vice versa for Ryo (which has been driving me mildly insane ever since I picked up the series). (It has to do with lines indicating shininess of hair rather than color. I clearly have a lot more to learn when it comes to understanding the visual vocabulary of these things.)

P.S. I was thinking of writing a Bikky-meets-Katou drabble for this week's theme. Who knows...