Actually, this is both a "remastering" and a "HD install" problem, as it only is an issue if I do both...

Remastering, I uninstalled the 2.6 kernel to gain some space. The resulting CD boots perfectly, but when I install the new image to HD it fails to boot. I was able to boot with a CD and chroot into the installed copy, and doing so I was able to edit lilo.conf to remove the reference to the missing kernel and run lilo. Then it booted perfectly. But I can't find where it got the reference to the missing kernel to add in the first place.