It’s not as easy as I thought, mainly due to the total lack of a working rarp/tftpd setup – NFS can be bodged. A list of what I did is available should anyone else want to try.
Of course, it’s not fully working yet in that the tftp stage was causing me problems last night, but there’s now an updated in.tftpd on the system so it should all ‘just work’ when I switch it on tonight… The page describes the steps needed to build the various utils to get the system booting, but not in too much detail – the steps that are show are mainly to help me do things in the right order should I need to redo it.
Of course, NetBSD 1.6 would solve all of this at a single stroke (yes, I know 1.5.3 is out, but it seems silly to jump now, given the amount of work required to migrate the web sites and users over to any new setup).