I would agree about the file part but as it is my home unit it could safely be left as RW. The car unit is only ever connected to by either my laptop or iPAQ and usually at an airport so that I can get new tunes on the portables and then fly away. Renewing a lease would never get a chance.

For the limited number of machines I have, a fixed IP for each stored in a RO hosts file would do. It doesn't have to be dynamic at all, just answer DHCP requests. Yes thats what I want, an empeg HCP server.