Are you thinking about to deploy this at "organization"?
I live and work in Brazil, in a Company Which has 1230 users, 231 branches in 231 diferent subnets in this country; one Domain Controller by branch. I´m a Microsoft Active Directory Specialist. I manage the PDC (Primary Domain Controller) and the remote Additional Domain Controlles from my computer. It´s very easy.
If you think about to deploy, maybe I can help you...
Look at: http://aplawrence.com/Misc/domain_controlller.html