I was wondering, Could I make a deb package that will include all the files necessary for the running kernel, including the kernel image?

I am thinking of changing to 2.4.20 or 2.4.18 but I am not sure if the new kernel will satisfy me and I don't want to loose the current kernel....I case the new one fails.

I also would like to have this backup in case I decide to customize my new kernel and I mess it up big time.

I don't have that much space on the hdd to make a backup.(By the way, Could this be a solution? If so how much space do I need?)

Usually you don't remove the old kernel until the new kernel is up and working fully. Kernels don't conflict.

When you install a kernel after the compile, you can add it to the boot list which comes up with LILO or grub, (In the install of a krenel-image deb if you use LILO it will ask do you want to add it automatically.)

If after a while you decide to remove the old kernel thats fine. Simply remove the files with the matching kernel numbers in /boot and the directory in /lib/modules.

USing make-kpkg is the best way to compile, and don't forget to use --appen_to_version.