With the latest rawhide, I get:
could not start boot splash: No such device /bin/plymouthd: symbol lookup error: /bin/plymouthd: undefined symbol: ply_answer_new
I can still boot if I select "Fedora-Base" or another older entry from the grub screen. In fact, there are the following entries in grub.conf:
title Fedora (2.6.27-0.382.rc8.git4.fc10.i686) root (hd0,0) kernel /vmlinuz-2.6.27-0.382.rc8.git4.fc10.i686 ro root=/dev/protee_vg/root_lv rhgb quiet initrd /initrd-2.6.27-0.382.rc8.git4.fc10.i686.img title Fedora (2.6.27-0.352.rc7.git1.fc10.i686) root (hd0,0) kernel /vmlinuz-2.6.27-0.352.rc7.git1.fc10.i686 ro root=UUID=5956dd1c-1eab-4487-91ca-e4c3bbc0fee6 rhgb quiet initrd /initrd-2.6.27-0.352.rc7.git1.fc10.i686.img title Fedora-base (2.6.27-0.352.rc7.git1.fc10.i686) root (hd0,0) kernel /vmlinuz-2.6.27-0.352.rc7.git1.fc10.i686 ro root=UUID=5956dd1c-1eab-4487-91ca-e4c3bbc0fee6 rhgb quiet initrd /initrd-2.6.27-0.352.rc7.git1.fc10.i686.img
If it helps, I installed 10-Beta and upgraded in place to rawhide. Replacing root=/dev/protee_vg/root_lv with the UUID as in earlier entries doesn't make any difference.
Cheers,