To have it in the cobbler settings file, I believe that would be an enhancement. You might be able to do via the default ksmeta options though, but I'd have to look at that to know for sure.
Yeah, at our site we have a grub_password in the ksmeta, like so -
cobbler profile edit --name=Fedora12-x86_64 --ksmeta='grub_password="$1$JUnkSAlt$OEQRO!U#@RHO#Rhu@#RU."'
And in the kickstart file:
bootloader --location=mbr --md5pass=$grub_password
It's important to get the quoting right for the ksmeta when changing the grub password from a command line, because of the $ signs. If you get it wrong, your kickstart ends up saying --md5pass=$!U. or some such, and then your grub is far more secure than you bargained for :)