Custom Case for Macbook Pro 15 Retina

I have been looking for a place where I can create a custom hard physical case for a 15 inch macbook pro with retina display. In my searchings I have only found custom skins and decals. Does anybody know where I can create a custom plastic (or something like that) case for a macbook pro. I DO NOT WANT TO GET A SKIN OR DECAL, BUT AN ACTUAL CASE.