As an administrator of RIS (5 servers within the enterprise) I can tell you that I have one server that is multihomed and is aldo a dhcp server. The server is used in our training room to build training PC's and is connected to our corporate network for the students to get internet connectivity. It is also using NAT. The system purrs!! I would agree that it is hard to tell if the system is functional until you try to build a pc, It would be nice if there was some type of monitoring tools. If you are going to be using custom builds you need to edit the default domain group policy to allow custom builds or you will never be able to display the list of O/S choices.
We used to be a Ghost shop but it was too much work keeping the images updated, RIS REALLY has been a blessing.