another alternative is here www.webintersect.com
it is an opensource social site kit.
The developer did an awesome job building it and he even shot a massive screencast collection on how it is coded step by step. the tutorials should be listed on the site as well as a download link.
(click on the green buttons in all the sections to see lists of all the tutorials)
I added my own blogging system to his project...which may very well fit right in to what you need. there is no dynamic menu builder exactly as you described but it would be pretty easy to add in.
my blog add on tutorial series is here part 1 watch?v=fZkGU9GSINQ&feature=g-upl
if you went this route, you may even forgo the whole user editing the sites main navigation system and just add links to student works on their own profile pages....would keep newbies from messing up the works in regards to the main navigation system
