Students and staff have an LDAP account. All mails go to your
Local WLAN offers 802.1x authentication, VPN and IPSec and unencrypted access with a web-based authentication gateway. To remotely access resources, you can either use VPN and mount your home directory via NFS or ssh to a public student server and do ssh forwarding from there or use X11 forwarding.
Pretty much all operating systems are supported. Detailed instructions and support are provided for Windows, Linux, OS X.
I am aware that this setup is not very common, but it does prove that it is indeed possible to run the IT of an entire university with thousands of students on Linux and support every major operating system.
I'm also sure that you university could easily support Linux if they only wanted to. Linux already supports nearly every protocol you could throw at it and most Linux users know what they are doing. Just enable some non-proprietary protocol, post an example configuration file and you should be good to go.