I read this morning that the University of Adelaide will be moving their 16,000 students to GMail with one substantial benefit being their mailbox quotas will increase from 250Mb to 7Gb (not to mention the huge savings from not having to host, store and manage these in-house anymore).
This seems a pretty smart move to me – plus you get some really nice calendar integration. You could have a separate calendar for every course the student is enrolled in, and then use the overlay feature of Google Calendar to have them all displayed together.
I remember asking a similar question at an IT workshop at UniSA a few years ago along the lines of “If GMail gives me 2Gb of quota, why am I stuck with a only 30Mb?”. If I recall correctly the answer given at the time was similar to that given by Adelaide regarding its staff accounts, but they’ve obviously been able to work through the legal and technical hurdles for their students at least..