Hi,
I don't think you need to create a custom live cd for such a trivial
thing. I agree with what Mr. Balaji has said. But if you're interested in
desinging your own LiveCD you can take a look at remastersys. A better
alternative would be to have a central PXE server with Ubuntu and have all the
other systems as diskless configuration. Another approach would be to have a
VNC server w/ Ubuntu and let the other users connect to it through VNC. Hope it
is of help to you.
With Regards,
--Kumaran R