Alan,
Your local ISP or a value-added Internet company could probably set you up with a scalable solution. SharePoint (TM) is a package which can be set up and configured on their servers to allow them to parcel out computer power to different users in a secure, segregated manner. This would allow an ISP or value added company with a few servers to service many customers. With SharePoint 2013 you can have access to all sorts of features which will allow you to provide test, pictures,and video. You can set up polls and tests. All of it can be protected by accounts. The problem is likely to be the expense of development and, to a lesser extent, hosting. And no, I am not a SharePoint developer. There are other packages which can do similar things.

But if there is a local, value-added Internet provider, they might be able t help you at a reasonable cost.

I wonder if your local school board or a local college would set up such a course. They could do all of the technical side and you might get either a flat fee or a per-student fee.


Regards,
Ed