Put an NAS on the network so you can save your work and put passwords/permissions with certain folders.
Not 10 user accounts, rather just 1. Make each machine a single, admin account. But put Deep Freeze on it, so it's almost impossible to mess the machine up with spyware, fragmentation, unneeded junk from the outside, etc. Also, it won't save passwords after a reboot, so it's more secure. Plus, if you have a machine fail, you can just diagnose it(eg. failed HDD) and throw a Ghost/CloneZilla image back on it.
Here is the flaw with this idea, and while yes it would work it depends on too many "ifs" and in my experience you are best off just doing the work yourself and taking the time to set it up right the first time. Trust me, I have learned the hard way many times.
How are you going to back up data and keep it synchronized to the NAS? Do you actually think your average user knows how to save things to a specific folder? Hell no, they just pile everything they ever create on their desktop. Also, putting up a non managed NAS is not a good idea. That can have some back fires. Someone navigates to the wrong folder deletes certain file, then you are doing data recovery, which is not fun and time consuming.
I would never rely on the end user to do anything other than use the computer. I would much rather do my job and make it so they can just use the computer and I take care of the rest. Sure you can batch file a rsync script out to sync files every night, but what happens if they turn the computer off that night and well, the HD fails at next boot?
Also, a NAS is hardly a good back up solution, I would say that it is a start of a back up solution.
Deepfreeze also causes problems with certain apps. This may or may not be a factor for this network, but I have had to disable deep freeze in the past to get certain things to work on client machines. Deepfreeze is a great app though, I won't bash it other than sometimes it is a pain to deal with.
Also giving the end user admin rights is not always a good idea. They could change their password, install bad software and if it isn't vista basically run everything as root.
I understand if you can't afford a small business enterprise set up, I get that. However, if you set it up the right way and spend a bit of money in the beginning it will benefit you more in the long run. After all time is money and down time is no money.