Thunderbolt is an encapsulation protocol. By default it carries displayport and PCIe, but it can also carry Ethernet frames. This is already implemented on OSX,

Thunderbolt is an encapsulation protocol. By default it carries displayport and PCIe, but it can also carry Ethernet frames. This is already implemented on OSX, just connect two macs together with a thunderbolt cable and you'll see a new interface appear with a link-local address. People have already used this for networking by using a mac with lots of thunderbolt ports as a router.