I'm not sure how i feel about coloring users by rank, but I'm pretty sure it isn't as important as you give it credit for (as implied by your 'emphatic' NO).

You can't make everyone equal by leaving off the color because we can still click the link and see a persons XP. Reputation is there for everyone wether it is a click away or not, so why not reduce site load by eleminating that click in some cases? Maybe making it more accesible is bad, I don't know, but it seems silly to pretend you can hide it by not making it easy to see. With demerphq's idea applied to all names then individuals could decide if they wanted to color different names. That might be more trouble than the benefit of saving those few clicks. Either way I would probably forget which colors where which and just think "look at all the pretty colors!";)

I guess after rambling about it I think its an okay idea. Not an emphatic yes, or no, but if i got a moment I might implement it, and if someone else gets a moment and implements it I certainly wouldn't be put off by it. So I'll settle for an emphatic MAYBE (if some feels the desire to implement it.)