Actually, in SU10 you can mass create users w/passwords. Just expand on the change log when you're finished to see the users, and then expand one more time to see their passwords.
Now, this does NOT allow you to also do mass changes to users passwords. I'm still not sure if SAP (4.6c is our version) has a way of handling mass password changes.
Thank you for your response as well Duffman. I will certainly inquire as to whether that's something we should try or just manually change the passwords in question. (As a brand new SAP user, I'm getting pretty good with security, but I haven't gotten the chance to really do much ABAP yet, which makes your suggestion a little hard for me!)