Some of you guys are WAY too "new school"
Vmware? Expensive.
Ghost? HAH! Ghost is absolutely not required for DOS. Ghost/imaging is only needed for newer systems that Xcopy just wont do anymore. Xcopy is all you need to duplicate ANY DOS/Win3.1, and even early Windows 95 systems. I used to build hundreds of systems per day with this method.
I also used to maintain a set of systems for a machine shop. Same scenario as you. 386's, 486's, with DOS. Mostly DOS 5.
Their CNC app only ran under DOS.... and was licensed/unlocked based on the hardware profile. If you changed ANYTHING, the app wouldnt run. But we could move the program and get them to unlock it based on a new computer (pay per incident). The real problem was - if our system died - we had to find an identical system - impossible.... and then had to call and wait for the cavalry.
First - find your hardware. I went out to an internet site that had tons of old Dell 486's for $10 each. Bought 10 of them, all identical... so we would have lots of spares.
Then, fdisk and format all the drives with dos - same exact version as they are running. If you dont have this, simply build a system diskette from their system by doing a format a:, sys a:, and copy fdisk and format to the floppy. Use this floppy to fdisk and format the drives of the new machines.
Get a backup of the old machine's drive. If you have no other way to do this, take ONE of the drives out of the new machines, and slave it. the new drive should be D:. Then simply boot the system clean (no running apps/tsr's) and run xcopy /s/e/v to copy all the contents of the current system drive to the new one.
Use the new drive as the master, and you can repeat this as many times as you want. You can have as many spares as you want. No need for anything complicated. This type of redundancy is cake.
We built out all 10 machines with the exact same information. When they have a problem with ANYTHING on that system (disk, power supply, motherboard, anything) they just unplug it, and go get another one from stock. Cost a whopping $100 bill.
Alternatively - if you want to copy this xcopy to a CD - and these machine have CDroms, you can make a bootable CD, or a boot/floppy combo - that can run a scripted format and xcopy and sys of the HDD, so if they ever screw it up, they can have an instand rebuild, and there your backup is on CDrom as well.