My very own Kernel build script for Debian/Ubuntu-based systems
 

https://launchpad.net/kernel-setup-sh

It can be easily ported to RPM or Pacman-based systems, however, just by editing line 4.

Good work, but wouldn't it be the correct way to make a package from the compiled kernel and then to install the package? This way your script would be compatible with DKMS and the kernelmodules for Virtualbox, proprietary drivers and so would be automatically compiled to fit the new build kernel. The way you do it Virtualbox, nVidia drivers, ATI drivers, etc will not work with the newly installed kernel. You can find more info for building packages from kernels here.

The problem is that that would conflict with my intention to have the script be able to allow you to customize the kernel (i.e. install only those modules to support *your* hardware) without having to run all those extra commands. That's why this script runs 'make xconfig' by itself in the first place!

Nothing wrong in running make xconfig, the packaging into a .deb-file is done at compiling time.

Okay, now version 2 of the script includes the kernel package option.

I have some questions, and some suggestions regarding your script:

1. Why is it necessary to install all those filesystem-tools and things like ppp and isdnutils?
2. You install grub-pc in your script. This is okay for all people that are running grub2, but if someone runs grub-legacy (i.E. Debian Stable users) this can lead to problem and may be unwanted. At least you can warn the users and let them ask a question, if they want to do that, or, maybe even better, ask a question with three choices what to install: no bootloader, grub-legacy, grub-pc. the update-grub command is also available for grub-legacy (in grub-pc it is only a wrapper for the grub-mkconfig command, for compatibility), so this should be doable.
3. And a suggestion for the future: Instead of installing all needed packages in the beginning of the script, I think it would be better (and the Debian way of doing it) to make a packe from your script that depends on all that needed packages.

By the way, as I already said, good work.