Batch adding users

A lot of the use of Omeka instances that I manage are in classes, and involve setting up many accounts for students each semester. So far the courses have been small enough that TFs haven't had a problem adding users manually, but I'm worried about scaling up to larger classes, with 40+ or even 90+ students

What I've found so far is that I can add users to the database, and then "re-send" activation emails one by one, which is loads better than doing it manually, but not as nice as doing the emails all at once, too.

I'm just seeing if anyone else has attempted something similar, or has any ideas on how to accomplish this, before I go digging through the user activation code to try to create such a batch activation.