Repairing flashing question ? mark on os x startup disk

Some useful pages:

general
apple
Mike's open firmware page
igm

an interesting product

can't open: error
macosxhints

My particular symptoms:
Flashing question mark in a floppy disk icon when you try to boot.
If you try to boot into Single user mode (by holding down 's' while booting), you get the error "Can't open: " repeated many times. Following this, you get the flashing question mark again.

Things i tried:
Resetting the PRAM (hold down command-option-p-r until you hear two chimes (after the first one you hear on the first boot)) - didn't work
Booting into the OS X CD and trying to repair the disk. The startup disk couldn't have anything done to it - all greyed out. Size reported as zero bytes.
Booting into OS 9.2 CD. Disk First Aid utility couldn't recognise the disk.
Booting into Open Firmware (hold down cmd-opt-o-f until the OF shell shows up:
set-defaults
reset-all (mac will reboot)
-- didn't work!

I think the disk is dead. RIP.