a long time ago one of my LJ friends posted this video, I have forgotten everything about her except that she was awesome and she sent me a link to it years later.
i wish i could remember who she was and i wish we were still in contact.
took a bit of mucking about, but i finally got the OSX 10.6 Server to work with DHCP and static reservations the tricks are to enable bootp and to enable dhcp_ignore_client_identifier this is how it should look in your config.