Revoke "drop database" even for superusers?

I've a bunch of databases that cannot be dropped in any case.

I was wondering if it is possible to revoke "drop database" permission for all users, in order that even superuser, if he wishes to drop a database, he will need first to "grant drop database" first.

I know there is already a safety that does not allow dropping databases in use - I just want to make even harder.

Regards,