I backup my A4000T monthly to tape using Diavolo Pro 2000. It has some sort of partition backup mode, too, but that might be for some other proprietary type (can't remember). I also do other online backups ... see below.
If that's not an option, then do you have two or more hard drives? I have three in my system, and all three of them have a full copy of my Workbench partition. All of them are bootable in case the one that I primarily use fails. The copies are updated nightly with the very simple to use "mirror" program from Aminet. Here is its Aminet entry:
mirror.lha util/cli 28K 95 Mirror drives, homepages, etc.. (v1.4)
I have it being run automatically at night from the program scheduler called EZCron, also available on Aminet. Doing a mirroring routine like this involves some extra playing around with partition icons showing up on the Workbench. Duplicates tend to show up anywhere they want on the screen. So, I make separate copies of the "Disk.info" files first, then put them back on each partition after the mirror is complete. This keeps the icons from moving around.
If the above sounds complicated and you still just want a "one file backup", then you could still use EZCron to start up a script automatically at night. That script would use your favorite archiving program (like LHA, LZX, ZIP, etc...) to compress all the files of your Workbench into the single destination file. Doing it at night with EZCron would require no intervention on your part once it's set up.
