You'd have to go into a store and look through the catalog, then you'd have to order them. I looked through it and there are a couple, they're just a low power, and fairly small.
From what I've seen though, most of the LED fans are a bright red and a bright blue, that when spun look purple (and a really cool BRIGHT purple at that). So that's always an option. You could always check out some other PC sites (pricewatch) for led setups. Guy I work with has a colored strobe type of thing going on his computer...looks REALLY badass. I don't remember the site, but I could ask if ya want.
"Caw, caw, *BANG* FUCK I'M DEAD!" - Top Dollar, The Crow
"Physics is like sex: It may yield practical results, but that's not why we do it." - XKCD
God created whiskey to stop the Irish from taking over the word.