I’ve now got automated installations of Debian Lenny using the preseeding method. Coupling this with using virt-install, I can have a Debian virtual machine installation in only a few minutes. No questions asked. More here
The virt-install command contains an extra-args argument, where you can fill-in the specific parts of the preseeding. I don’t want to set an IP address in the file as it’s going to be used to build lots of machines, so I just specify that at install time. The URL part is where out preseed config file is stored.