Limited user change network settings?

I have a group of users who must be kept on as *Limited* users.
They are the reason spyware and viruses exist–these guys get
them all if they can install anything whatsoever. You know the
sort of user I mean. They are using Gateway 450SX4 laptops
with Win XP Pro SP2.
Unfortunately, they must travel as part of their job. We are not
on DHCP at work, and they stay at hotels with Internet access
that do use DHCP–sometimes using ethernet, sometimes using
wireless.
How can I give them access to change their network
connections, but otherwise keep them “Limited/Powerless” users
in all other respects? Putting them on “Network Operator” user
group gives them install privs. That is the LAST thing I want to
happen.

Thanks