I agree with FN-GM's comment above, but I am curious how you'd manage a network like this. For example with each pupil having their own user account, this allows each child to create their own portfolio of work. With your system or idea they cannot do this. Also, if you have/had single user accounts how would you control access to sensitive data on a file server? Permissions just wouldn't be possible to setup.
Now I'd like to not throw the baby out with the bath water (e.g turn each computer into single admin user and just use the existing server as a file server as I like the Viglen printer/file restriction management) but I'd like to completely remove any computer restrictions from all users (lets not get into the rights and wrongs of this - its what I'd like to do )