<< I never said on the domain, I said on the domain at a time. >>
Client access licensing has nothing to do with how many machines can be on the domain at a time. It determines how many machines can access the resources of the server at a time (fileshares and other resources).
AFAIK, there's no licensing at all needed to put as many machines on the domain as you'd like, as long as they're not accessing server-side resources that require client licenses.
Also, the link you provided details SNA client licenses, which are different (but the same theory) as the W2K client access licenses you get when you buy server.
SMB servers, terminal servers, and SNA servers all require different licenses for their clients, even if the services are all running on the same server, and all three clients are on the same workstation, that workstation (or server) needs a SMB client license, a terminal services client license, AND an SNA client license.