One question: Why do you want to use AD? Isn't OpenLDAP good for it ?
- Install a M$ server at each location sharing an Active Directory.- Install DNS on each server with zone in the AD. - Have Dhis nsupdate the DNS running on each local server - Rely on AD to replicate the zone. (For all it's shortcomings, M$ implementation of DNS is supposed to be able to do this!).
Artur