We have almost all sites where we have multiple roles and we need a different profile for each role. This was so far rocket science since we did not have a mechanism to create different looking registration forms per user role. We handled this situation post login when we asked people to create profiles as per their roles.
Also, we have an issue of assigning roles when logically a person should be able to choose their role and admins should simple approve or disapprove of it.
Walking by the PC
One September Afternoon
I found the solution
But not very soon