This is no way as sophisticated as other solutions but it works for us:
We run courses by year groups so that every class in the year get to see one site. Past files and resources are kept when the class rolls forward (LDAP again!) to a new year. For items like assignments and examples of good practice I just put a table into a web page allowing students to access past examples (suitably anonymised) and the grade-area they received. So, students get to see good practice before they start the assignment.
The only issue this year was that I rolled classes forward before the sysadmin who promptly deleted everything I'd done assuming it was old work
Paul