As I understand it you can already do this by changing # defoptions & altoptions line in /boot/grub/menu.lst. ea mine is: # defoptions=rootflags=data=writeback hdc=ide-scsi hdd=ide-scsi.
Now update-grub will add this options to the end of each kernel; this script is executed after a kernel update.
It has begun to drive me crazy that menu.lst is changed everytime I have a kernel update. For some reason, it always thinks my SATA is in a different place, and I always have to move it back, even though I have corrected device.map.
Seems like a simple thing to me, change only what you need to when you update the kernel.
As it has been said, this can be done easily with defoptions option and such, but not all users find it right away when messing with menu.lst . Maybe add a clear help message there?
For example:
# If you want to add a boot option, consider adding it to defoptions, or it will be forgotten the next time a kernel update is installed.