We finally joined ZCS with SAMBA/POSIX accounts. Your WIKI is 'perfect' - although we will send some minor addons to your article
Anyway from the whole list of users we have some which we call systemusers. These accounts have nothing to do with emails but only exist for uidNumber and/or SambaSID. However there is no way (or at least we don't know it) how to add new USER without decreasing licensed accounts.
Is it possible at all? Do you plan to add such feature to ZCS?
Our ZCS is : 6.0.4 on Ubuntu 64bit 8.04 LTS