OK, sorry for dragging up an old post, but I though it would be good to follow up.

Turns out: this is not really something MS wants you to be able to do.

Tony, I tried your suggestion, but didn't even have the option. I got into the profile settings and the "Copy to:" button was grayed out.

I found several sites that describe steps for how to convert a domain profile to a local profile, but at best they all describe very wonky ways to do it. Most of the time, it involves just giving permissions to every file in the Domain User Account folder to a Local User Account, granting the same to everything under the HKCU, and then spoofing the user profile address in the SID in the ProfileList key.

On one computer, this process actually eventually worked! But on another, it really didn't. I got to the very end and everything looked fine, but for some reason the now-local profile had tons of missing rights. It was so bad, that nothing would load in the control panel, I couldn't bring up the network and sharing dialog, the network adapter didn't know how to connect to the network, etc. Some programs opened, but Outlook couldn't find the profile that was already there.

Anyway, in the end I'm going to cross my fingers and merely remove the server from the network. All the users will still be able to access their accounts, and their passwords will still get them in. When a user leaves, I'll simply remove their computer from the domain and set them up with a local account.

Yup, I should have this project done in 5-10 years...