Would it be possible to have the registration function actually create a new security role if it doesn't exists? In my case, a specific security role will be able to create events, but not create security roles through admin or superuser. Having the Calendar and Registration module create a security role for a specific event would be a much cleaner solution.

Well,

This is a good suggestion. However, it maybe a little lose for normal user to create new roles.
I would still vote for creating a new role first, and then having it added for that person... Nevertheless, we will discuss with our developer team on this.