author_base rewrite for each user role.

After searching for hours and hacking code myself, I have been unable to find a way to create multiple author_base rewrites for each user role, ie: “example.com/admin/Mike” while at the same time have “example.com/publisher/Aaron”. This feature should be built into WP seeing as how easy it is to rewrite the slug for custom post types, should be equally as easy to rewrite slug for each added user role and existing.