Unless you're thinking of huge online courses like Udacity/Coursera, I don't think that's really a thing?
If it is, I'd be fascinated to learn more.
I mean, the logistics would be pretty wild - even a large university's largest lecture theatres might only have 500 seats. And they'd only have one or two that large. It'd be expensive as hell to build a university that could handle multiple subjects each admitting over a thousand students.