Edge only displacement textures, can this be done?

I want to make simplified toon characters and I wish to add simple jagged edges to represent fur.
Where they would appear is only where the mesh normals are exactly 90 degrees view from the camera.
They would match the texture color from that location and lighting affected.
Where I can paint a vertex group to where I want the jaggies to appear and by how much.

I was thinking maybe use freestyle to make such edges or use an adaptive displacement texture?
This node setup might not be possible or maybe it can, I am unsure.
I never seen this done but would be amazingly fast to make toon fur.