We took a look at the 1TB VelociRaptor back in April. Well now Western Digital went and stuck a pair of them into an oversized My Book chassis, connected it via Thunderbolt, and voala:

This is a nice little external storage device that can be configured as a RAID 0 or 1. My Book Duos can even be daisychained to support RAID 10! Daisychaining allows up to four My Book Duos to be connected simultaneously. The price is a bit steep, but seems to be in-line with other Thunderbolt enabled products. More to follow once we get a sample in for review!