On my board we have a group called New Members that contain all users with 0-9 posts. Only this group does not have permission to use the PM function of the site. I would really like the ability for moderators and admins to be able to PM a user, regardless if they have PM permissions or not.

Wouldn't that defeat the purpose of disabling their PM system? Whatever your purpose is for contacting these members, why not just use the email system?