My name is suddenly bold and pink! (there are so many jokes which could be added to this sentence, I wouldn't be British if I didn't giggle just a bit)
I am guessing you are playing with adding a more visual style to your ranks!? Well, since this forum is all about our opinions.. Can I offer mine?
I don't like it! :'(
I have seen a few sites which change the colour of user names based on ranks, and I have to admit, I find it looks... Well a bit, garish.
What might work, is pick one or two colours (hue) and use different brightness or saturation settings to denote rank. That way the change is subtle, doesn't break the design principle of the site and doesn't make my eyes bleed!
actually thinking about this a little more, I see no reason why the names should be in colour, perhaps the icons are the only thing that needs a bit more colour.
Icons are hard to get right because you are trying to fit in a lot of detail in a small amount of space, colour makes that easier I think.