The large-scale script I've been using is available on the WeBWorK wiki, in the administration section; there's a page with contributed scripts there: contributed scripts. My script is called wwManage, which does a bunch of stuff including management of course rosters.
I'll put a second script there as well, which is my cl2ww script that creates WeBWorK classlist files from the format I get when I grab rosters from our registrar.
The last script I have is a stand-alone that copies student work. There's one glaring issue with that, which is that it relies on the database structure in WeBWorK being what it expects, and that's likely to change a little bit as WeBWorK evolves and a lot when it goes to database ver. 3. If you want to see that I can post it or send it to you, but I'm hesitant to put it into the general documentation because of its reliance on mysql calls to insert things into the database directly.
Let me know if that doesn't make sense or doesn't help.
Thanks,
Gavin