I've recently applied this with a few tweaks:
https://fedorahosted.org/pipermail/cobbler/2008-August/000514.html
This allows for the following:
cobbler distro edit --name=foo --kopts-post="noapic asdf=jkl"
In the above example all distros will have the default kernel options on
the installed OS include noapic and asdf-jkl. By contrast, "--kopts"
in cobbler only covers the kernel options of the system as it is
installing.
--kopts-post works on distros, profiles, and systems, in the same syntax
and way that --kopts works.
For users upgrading to 1.1 and later, this value will default to no
kernel options.
This is implemented by SNIPPET::post_install_kernel_options, which will
be included in all of the stock cobbler templates. This snippet is an
example of how we'll be including more and more snippets with cobbler
over time to make the kickstart templating in Cobbler more powerful and
flexible. For upgrading users, you won't have this snippet in your
kickstart files, so add it anywhere in %post if you want to take
advantage of this new feature.
--Michael