B&H has the Western Digital 2TB My Book VelociRaptor Duo Thunderbolt drive for $449 (reg. $649). This drive includes two 1TB 10,000RPM VelociRaptor hard drives with transfer speeds up to 400MB/s over Thunderbolt. I got 350MB/s-ish speeds in my real world tests with it. Check it out here at B&H Photo.