ATTENTION !!!! MOTHER OF ALL QUESTIONS

Running W2k prof clients and nt4.0 servers.
Need to find out computername that a user is currently logged into. I know nbtstat but i have 500 users and i dont want to wait for it to cycle.
Is it possible to call from cli a remote registry and pick this info up or what other ideas can anybody come up with. Ive searched usegroups (thousands) and nobody can get this right.