you can use the grub configfile command
check out the grub manual...
http://www.gnu.org/software/grub/man...tml#configfile
i haven't tried this but it looks like you can load a config file from anywhere.
so you'd have a /boot/grub/menu.lst with something like
configfile (hdx,y)/grub/config
where (hdx,y) is your fat partition
this should mean you wouldn't have to change your boot partition, just add menu.lst with a single line in it, and remove your existing grub.conf, else it will load that by default instead of menu.lst