My understanding of this is that NO; NetApp cannot be a DFS root. However....(patching in from another email thread I had going internally)
The VFM namespace availability policy can create a widelink namespace on the FAS to have the same DFS structure as a DFS root. The admin could have a separate DFS root on a Windows host strictly for admin purposes. They'd manage the DFS root through the VFM UI and let the namespace availability policy duplicate the changes into the widelink namespace (netapp). By connecting CIFS clients to the widelink namespace, the admin gets the benefits of DFS along with the reliability of the FAS .
check in the video at 7:36s and you can experience how you can replicate an entire DFS root structure into a filer for HA purposes. The nice part about this is you can have the resiliency of a domain root, with the expandability of a server root (50K links, IIRC).
so the answer to your question is NO, but we can do something really close.