2D Sprite Animations - Best way to making color changes to sprite animations

I have these large spritesheets that contain many frames of animations for a generic character. I've put one into the game using mecanim and have it working in code perfectly. My problem now is that I want some more variety in these characters, different hair colors, different skintones. The only way I can imagine doing this, is by changing the colors on the spritesheet itself. That's fine, that part is easy to do. I'm not sure how to hook these new spritesheets in to my animation system without having to remake animations and controllers for each individual spritesheet. That would take a seriously long time since each of these spritesheets has many animations. The frames of all these different spritesheets would be the same, the only difference would be colors. Are there any tools to use to handle things like this? Is there some easy way to do this that wouldn't require me to remake everything. Thanks