If I could get one good mask for V4's eyebrows, I'd very happily use that.  I don't MIND the painted on eyebrows in some cases but I don't want all my black haired girls to have red eyebrows.  Masks are awesome and have so many uses.  Using a mask in the material settings allowed me to do this (shout out to OrcaDesignStudios for this.  I used his initial set up and learned a LOT from it).

www.renderosity.com/mod/gallery/index.php

then, like Momcat said, get a nicely detailed displacement map for the brows and it won't look painted on.