User Registration plugin with modal capability

Here’s what I would like to do: when users click the menu link “Appointments”, I want them to be taken to the Appointments page (which uses the Appointments+ plugin). but I would like a modal dialog displayed over the appointments content. The modal will display a Login/ Register/ Forgotten Password form. Once the user has signed in or registered through the modal window, then it closes and displays the appointment content of the page.

Do you have a user registration plugin that has this capability?