Custom Registration Form for Moodle 2.2

I'm looking for a custom registration form in our Moodle site. What we need is a solution to be able to approve/deny user registrations. In other words, user should be able to signup, but instead of sending a confirmation email with a link to activate the account, I would like one of these options: A- To have a plugin (only visible to admins) which lists the amount of users who have registered and then an option next to each name to approve or deny the request (something like when a friend adds you to facebook) so you can have a complete control over who is signing up. B- A special code field which user will have to input on the registration form in order for him to receive the confirmation email. Such code should be able to be changed oftenly. C- Any other option you propose that does the trick. Thanks! M.