Sharing is important....
Over the weekend my laptop died - complete failure of the hard disk. Being a professional I had of course backed up everything NOT. What saved me was sharing - I had shared everything I was working on with other people for feedback, comment, etc. By noon Monday I had all my important work back.
This is not a technique I would ever advise to anyone, but it does illustrate the concept of a simple backup strategy through statistical copy. It does not require sophisticated hardware - just lots of cheap hardware. The MTBF for most computer hardware is probably measured in years now and so for most non-critical data this is probably not a bad technique.
Could this be done with cron,bash and Samba? - seems pretty simple to just keep a list of directories to copy around the network and ensure that all key data was statistically guaranteed to be more than one place. A project to work on in the mythical spare time.