With a shell script you may easily create a tarball archive and gzip it, but I can't tell the same for the burning process..
Try doing a search on Linux related sites & Freshmeat and the likes...
Write a script that will dump your system and then cp it to a command line burning software. such as CDRDao. Ill try to work something out for you email me exactly what you want.
Are you running a regular distro of Unix or are you running Linux? I know that Ghost 2002 will do Linux systems ( I just installed it on a new box I built for my sister with 2000 Pro on it and saw where it mentioned it ).