Ah, finally someone making some sense. Universal Audio and Apogee have introduced TB interfaces also. On the video/film side of things where I am, all of our storage is external and in a separate room. We use fibre to connect to that so I could seen needing an expansion chassis for the the card but that would be mounted under the desk and out of sight.
Expect SAN vendors to add support for Thunderbolt cabling.
One common misconception about Thunderbolt is that it is simply an “external PCI Express”. It is not. Thunderbolt is a super low-latency, high-throughput packet switching fabric with crazy time synchronization capabilities (8 ns). It can support any network topologies, it’s just that Apple only utilized line topology (2 ports) before Mac Pro. Both DisplayPort and PCI Express protocols work over Thunderbolt protocol (with an added twist that Thunderbolt ports can give out DisplayPort signal directly, so a user can attach non-Thunderbolt DisplayPort display).
With Mavericks, Apple has now added a third protocol, IP. It would be trivial for them to add Fibre Channel protocol as well. Fibre Channel already supports Ethernet cabling (FCoE), and it would be even easier for SAN vendors to add support for Thunderbolt cabling (let’s call it “FCoTB”), as Thunderbolt does not have packet congestion problems of Gigabit Ethernet. Since you won’t need to buy expensive FC HBAs or 10GbE NICs, you’ll be getting Fibre Channel for the cost of Thunderbolt cables and you’ll be able to connect a 16GFC link to any Mac with a TB2 port.