A great article for its purpose - well done.
A note, however, that software vendors should not assume that they will be permitted server admin access to a data server to install their app. It is worthwhile to have this as one option, for the shops that don't really manage their servers.
In better managed situations, people like me will not permit vendors to use server admin for any purpose. I will go ahead and set up the db according to your specs, and give it to you with dbo access: you can do anything you want inside the boundaries of your db, but no special privs on the server.
Otherwise, I have no way to verify the security of the other databases.
Again, not a criticism of the article! But a warning to those who would use it - to do it appropriately.