Most Sysadmins know how to set up a basic chroot on a mounted filesystem (mount-binding dev, proc and sys) but this does not work in any case; for a complete chroot setup you would aso need dev/pts dev/shm, run, tmp, a working resolve.conf and more. After you have set it up, and you want to bring it down, you have to do a lot of typing again. But wait! There is a better solution.
There is a script called arch-chroot shipped with the Archlinux distribution, but it is not limited to be run with Archlinux. It works on any linux distri!
you can install it like this:
chmod +x arch-chroot.sh
Using this script, I was able to install grub without getting errors like:
grub-install: error: cannot find a device for /boot/grub (is /dev mounted?).
grub-probe: error: cannot find a device for / (is /dev mounted?).
If you are looking for a perfect rescue system, i recommend the archlinux install image; it contains the arch-chroot script, all low level tools needed to format hard drives and even supports mounting of ntfs read-write and accessing samba shares.