WoW!
I have seen a similar, much smaller setup using IDE Raid. The nice thing about raid, SCSI or IDE is that if you have a hot swap spare in place or not, you just remove the bad HD and replace and away you go.
SoulAssassin, they do not have to physically move the hard drives off-site. They can set up another backup unit(s) at a remote location fo an off-site disaster recovery site. In fact the article stated that the units didn't even have to reside together, just needed a gigabyte connection to the network.
Before I got laid off, we were testing software that captures data as it's being changed, and if the server(s) that is is a mirror of dies, it takes over immediately with little or no data loss. It also didn't need to be co-located with the servers it was backing up. I wasn't involved with the project, and I don't know if they ever put it into production or not. There were plans to place one of these backup servers at each of the 4 data center locations to back up one or more of the other sites as part of our disaster recovery program.