Hi Aaron. Thank-you for your post.
They do have some performance and planning information available in
the Windows 2000 DNS white paper:
http://www.microsoft.com/windows2000/techinfo/howitworks/communications/name
adrmgmt/w2kdns.asp
One limitation to be aware of is documented in this article:
267855 Problems with Many Domain Controllers with Active Directory
Integrated
http://support.microsoft.com/?id=267855
Other than that I haven't seen any documented limits.
I hope that helps.
Tim Rains
Product Support Services
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no
rights.