Any experience with ustream?

https://watershed.ustream.tv/

Imagine an instructor teaching a cloass with a live group in front of him.

And then imagine 2-50 peaopl watching / listening via this.

The instructor goes though a detailed powerpoint presentation. I would have to take that presentation, and present it in a window in the interface. Maybe as simple as converting to PDF and let the end user page back and forth.

I need an web interface that allows them to login to get to a certain video at a certain moment.

Once the seminar has started, I need a feedback mechanism that queues questions to the instructor.

Every X minutes, I need a popup that asks the user a question. The users will have to respond in Y seconds, and the popup should timeout and go away by itself if they missed it.

The results of the popups need to be aggregated into a single report do determine who passes / fails.

The standard educational ASPs (not many, but they are there) charge more per hour of desktop or video shared than the profit per person for the online clients, so it seems to make sense to build VS buy for this.

So - any pointers? Someone want to be an devils advocate and tell me why this won't work, or any additional features you think this type of application should have?

How long would YOU take to design, code, and implement this type of solution. If it is a lot faster / cheaper than I think I can do it (not saying how long much) are you open for some contract hours?