Comment 10 for bug 107774

well the work around while the kernel is getting built is to go in and change the initramfs package to only use the files listed.
I don't have an ubuntu box in front of me so bear with me...
edit /etc/initramfs-tools/initramfs.conf (??) and switch the first option to list (iirc). Then edit the /etc/initramfs-tools/modules.list file and add the appropriate ide drivers for the root hard drive, remember to include the filesystem drivers as well. I ended up having something like:

sis5513
reiserfs
ide-core
ide-disk
generic

Then regenerate the initramfs file (mkinitramfs -o /boot/initrd.img-2.6.20-4-386 2.6.20-4-386 && mkinitramfs -o /boot/initrd.img-2.6.20-4-generic 2.6.20-4-generic) and I was able to boot just fine, udev didn't even try to autoload the pata driver so you should be good.