What is your site's policy on how to create user account names?
     Is there a server that has user uid/gid information already that you can query?
        (Is it secure enough to do so?)
     After writing their passwd/shadow, do you need to push yp?
     Do you have to set quotas after creating accounts?
     Do your skel files look like <local.*> or just <.*>?
     Do you want to be nice and touch /etc/mail/<username> (and set owner/perms)?
     What kind of beer was that?  :-)