Well I shouldn't say "rival" exactly, but one woman that I think has hair just as wonderful as Nikki if not more so is Jacklyn Lick.
Here is a clip from that shows off her wonderful hair along with her incredible body. The first link shows you some screen captures while the second link takes you to the clip itself. I know you all love Nikki just as much as me, but I personally think you got to rank Jacklyn up there. Hopefully this clip will make you a Jacklyn Lick fan just as it did with me.
Screen Captures
celebritymoviearchive.com/tour/movie.php/6638
Clip of Jacklyn Lick