Zero data integrity...
WD's setup is extremely bad for normal use. Each MyBook setup for RAID 0 meaning both drives in each MyBook are additive with zero redundancy, if one disk goes bad both lose data completely. Then they stripped them RAID 0 between the 4 MyBook's using OS X software RAID. So any one of the 8 disks fails, the entire 24TB's is scrubbed and unusable.
Once Tenscompliment's ZFS comes out (very soon) then you will have a ZFS option to protect those drives. What we really need is some dumb multi-bay box that holds 4-6 hard drives and provides TB interface. All 4-6 drives would show up in OS X as individual drives then you add them to a ZFS Disk Pool and set it up for ZRAID (single parity or double parity -- one or two disks can fail without data loss) and however many snapshots you want to make.
I was looking at eSATA 4-6 bay external drive bays and found they run around $124 and a PCIx eSATA card for a MacPro. The only other cost is the disks themselves which is a PITA right now with the disk shortages.
But if someone sells a dumb 4-6 bay drive container that includes 2 TB ports and doesn't try to do hardware RAID, etc. I will jump all over that!
The nice thing about ZFS is it is rock solid and can handle any type of drive. MacPro internal SATA, eSATA, TB, Firewire, USB, etc.
Geez, I remember my old ISP servicing a couple thousand dial up customers on a single TB of disk space spread across multiple servers. Now you can have that in a laptop! How far we have come...