Now.  That said...

As far as Zen is concerned,

RANMA CHAN IS A RED HEAD.  SO THERE.

Thank you.  Zen feels much better now.

Heh, thats the way to tell 'em. YOU GO ZEN.

Ranma-chan is a red head because she isn't nearly as cute with black hair. As 
for the eyeliner, it's Ranma's feminine side speaking out ;)