root nameserver hardware requirements

[jacob at freecommunity.com]

some guys here on earth are setting up a set of nameservers to take over
dns duties for a couple of isps.  they have a few thousand zones each.
they expect moderate to large growth.

the implementation they finalized on was two cobalt's running linux as
"the primary" with a hardware frontend load balancer and a netapp
(shared with other applications) for common access to the zone files.

i claim that is far more hardware than necessary and needlessly
complex.

i am wondering if anyone knows what an average hardware configuration
is for a root nameserver.  this would be a nice point of reference.
also, if performance is an issue, would it be wise to keep the
recursive/caching and nonrecursive functions on seperate machines?

i have searched the bind-users mailing list and have found several
posts to support my view, but knowing what the root servers are setup
would be very helpful in arguing my position.

any input is greatly appreciated.

-jacob martinson