scalability

We're exploring the idea of using Drupal for a university-wide ePortfolio system. The feature set certainly looks like it's there (custom content types could organize different page templates. Other modules could help facilitate collaboration and communication). The big question for us is its scalability. Would we be able to scale Drupal to 50,000 to 100,000 student sites? Conceptually each student would have their own mini-site to showcase their content.

Any recommendations on the way this could be architected?

Thanks for any input you can provide.

-Retiarius