Re: Sorry, but Peter's right - you Just Don't Get It.
Oh, *that* must be why all the other consultants are toting around laptops with thirty-eight network cards in them -- one for each LAN they ever attach to! No, hold on, wait a minute... Hey, guess what -- they *don't*!
I would not do what is being suggested here, and I doubt that any of the consultants you see wandering around do it. Any client with enough infrastructure to need a consultant will have a DHCP server that sets all that stuff up on the fly. It's the very same principle as dialing up to the Internet over the phone lines. You tell the network "I'm here" and it gives you an IP address, a network to live on, and a gateway to the rest of the world.
I was at IBM - people had several machines, laptops, labs, etc. Issues like this never arose as people went from room to room to experimental setup to lab to conference etc. It is so easy to configure a DHCP server that any network with more than say 8 nodes should use it. If you ever had a real need to reconfigure your personal network settings from the ground up, then that is the responsibility of the client in any case.
-drl