Thanks a lot for linking that plug-in, Visvanath! It looks exactly like something we're looking to implement!
If you want to keep old courses available on a read-only basis this plugin may help
https://github.com/marcusgreen/local_read_only
It is in use by at least one significant UK university.
https://github.com/marcusgreen/local_read_only
It is in use by at least one significant UK university.