I would like to think that you can setup a DHCP server on the server (assuming you are using ubuntu here) without it directly affecting FOG too much. Here’s some basic instructions for installing a DHCP server on it’s own. There may be some modifications you have to change in TFTP, but I can’t guarantee that.
[url]http://www.ubuntugeek.com/how-to-install-and-configure-dhcp-server-in-ubuntu-server.html[/url]
Outside of that, I would point you to this: [url]http://www.fogproject.org/wiki/index.php?title=Backing_up_FOG[/url]
[url]http://www.fogproject.org/wiki/index.php?title=Restoring_FOG_from_Backup[/url]
That page will show you at the very least what areas of FOG you can backup and then restore, so that if you do blow out FOG and reinstall, you could easily get your database and images back.