Thanks for the suggestion Ghostofmacbeth, I'll have to play around in the material room.   I do have a method for changing hair hues like that but it does rely on a material node, I'll have to see how I can work with the displacement for eyebrows only plugged in since there is no separate material for the brows.

I remember Traveler had made eyebrow props for Posette waaaay back.   A pair of morphable transmapped eyebrows would be a great add-on for V4!