If you want to append additional parameters to the kernel command line, configure it via GRUB_CMDLINE_LINUX_DEFAULT or GRUB_CMDLINE_LINUX in /etc/default/grub.
No, I want to generate an extra entry for each kernel for runlevel 3, automatically.
f you want to add further entries to the grub boot menu, that can be handled by a script in /etc/grub.d/ (see the README in that directory).
It's not worth duplicating and hacking a 130 line bash script just to save some typing at boot time, I think :)
<rant>Incidentally, that README file doesn't really achieve much. What are the parameters to those scripts? What is the specification for their output? (Presumably something approximating the example file in /usr/share/doc/grub-pc/examples?) This information isn't available in the man pages for grub, update-grub or grub-mkconfig either.
</rant> Thanks anyway :) - Jason