2D Sprite color palette swap

I'm wondering what is the best way to do a color palette swap in Unity for 2D sprites. I'm trying to have sections of my sprite (like visible skin) to change color without changing other parts of the sprite.

I looked at the masked tint method (http://wiki.unity3d.com/index.php?title=Masked_Tint), which seems like what I'm looking for, however, if I'm not misunderstanding it, I would need create a material for each sprite, which is not ideal. I could also go through it pixel by pixel and change the it if the pixel matches the color I want to swap. I imagine doing that would be quite the performance hit.

Has anyone implemented this for their game?