Media event set for September 9, launch likely ~10 days later.
Seagate Starts Selling GoFlex Portable Thunderbolt Adapter
The GoFlex series is a set of external hard drives with interchangeable interface adapters that allow their hard drives to switch between different interfaces. Existing adapters include USB 3.0, Firewire, and eSATA. This new adapter offers Thunderbolt support for existing portable GoFlex customers. One reader notes that the interface is simply an SATA interface, so this adapter could be used with any bare 2.5" SATA hard drive.
Seagate first announced the Thunderbolt adapters at CES and is also planning on offering a desktop version of the adapter for $199 in February.
Macworld had a hands on with the portable unit and found it did indeed perform faster than Firewire 800 (and of course USB)
Using the new Thunderbolt adapter, we saw write speeds of 78.8MBps, or 40 percent faster than FireWire 800. Read speeds were about 79.3MBps, about 13 percent faster than FireWire 800.The performance gains were only so big since they were testing against a single non-SSD drive. Previous Thunderbolt benchmarks have shown much larger boosts but only when using SSD and RAID configurations, eliminating some of the drive bottlenecks.
As it's aimed at the portable market, there are some other limitations with the device. The device only has a single Thunderbolt port, so it must be at the end of the chain. However, it is also bus-powered so no external power supply is required. (The upcoming $199 desktop model reportedly will have an external power supply and additional Thunderbolt port.) Also, the $99 price doesn't include a Thunderbolt cable which still runs $50 at the Apple online store.
So, the entire setup will add a $150 premium to your hard drive purchase, but is one of the few single-drive external Thunderbolt drive options available today.
Update: Note, that Seagate's GoFlex adapter is simply a standard SATA connector, so it could be used as a bare 2.5" SATA Hard Drive -> Thunderbolt adapter.