distro for PDC/AD

I'm not aware of any specific distros for that purpose. However, you can accomplish this using Samba 4 much more easily then in the recent past.

I'm actually in the process of rolling up my own Debian based distro for that purpose, sort of. My actual goal is to make a distro that can be used to replace 100% of the functionality of MS Small Business Server, with a simple interface for managing the features / services (some custom code / apps). I also intend to focus heavily on simplifying PXE booting and supporting thin clients (both hardware and software).