Wherein I learn about initrd

Post summary: will someone PLEASE port a recent KVM to any BSD? There's beer in it for you.

I've been attempting to upgrade my diskless virtualization cluster to Ubuntu 10.10. Diskless boot worked fine in the ESXi test area, but real hardware would not boot. This same hardware booted fine with Ubuntu 10.04 and 9.whatever. When I looked at the console, I saw:

ipconfig: no devices to configure
ipconfig: no devices to configure
ipconfig: no devices to configure
ipconfig: no devices to configure