The cabling for Apple and Intel's next-generation peripheral interconnect will be getting an upgrade this year, says IDG. Thunderbolt optical cables will be shipping in 2012, according to Intel; current cabling for TB is all copper-based.
The PCI-based Thunderbolt technology has always included optical cabling in its roadmap, but the costs of fiber versus copper and the development lead time meant that the initial implementation didn't include the optical option. Mac Thunderbolt ports and peripherals, fortunately, should be compatible with both types of cabling; swapping out one for the other should be straightforward for the most part.
The only catch with optical TB cabling is that bus-powered devices (like Elgato's new Thunderbolt SSD drive) will probably require a power injector or standalone power supply. The optical cable's extended run length (multiple times the six-meter copper TB cable limit) means that power can't be dependably run through it.
Thunderbolt peripherals have been thin on the ground since the first TB-equipped Mac models were announced early in 2011, but more and more are starting to arrive now. Sonnet's ExpressCard adapter allows for multiple interface options for TB machines, including FireWire 800 and eSATA.