79768 Classroom script

Need a script that will allow users to join the site. Once they have joined, they can either join existing classes or start thier own classes. As a teacher of the class, they should be able to set leave lessons plans in html or text. They should also be able to give test which would be multiple choice or T/F and the test shoujld grade itself. There should be also a discussion board for each class. They can decide whether to make the class a paid or free class. If paid, they determine the cost. Teacher can approve or delete class list and the class itself. As an admin, I can set to approve teachers or have them automatically allowed to set up classes. If teacher decides their class is a paid class, then it credits to my account through paypal and I pay the teachers. Admin able to delete or edit classes and/or users. There are several open source project similar to this at: [login to view URL] but none of them have all the features mentioned above.