For those looking for a Thunderbolt option for Pro Tools HDX or Native cards, then the Sonnet Echo Express may just fit the bill, it’s not cheap at around £1000 UK, but it looks very cool. In their words…
3-Slot Thunderbolt Expansion Chassis for PCIe Cards
Sonnet’s Echo Express III enables you to connect three compatible full-size professional video capture, audio interface, and other special-purpose cards to your iMac, Mac mini, MacBook Air, or MacBook Pro with a Thunderbolt port. The Echo Express III integrates a universal 300W power supply and includes a 75W auxiliary power connector for cards that require supplementary power. Even with all that power, the III is enviro-friendly; it automatically powers on/off when the connected computer powers on/off or sleeps. The use of larger, slower-spinning fans in the Echo Express III makes it the quietest Echo chassis yet. Two Thunderbolt ports support daisy chaining of up to six devices to a single port on your computer.
Desktop or Rackmount
The Echo Express III is available in two versions, the IIID (desktop) and IIIR (rackmount), to suit your workflow needs. The IIID’s form factor makes it easy to transport. The IIIR mounts in a rack space 2U tall, and is just 15.75” deep, making it perfect for use in a wide range of popular mobile racks, carts, rack-bags, and server rooms as well. The IIIR even saves space for other equipment—with the optional Echo Express IIIR Mobile Rack Kit, you can install one or two mobile rack devices in the IIIR’s rack enclosure.