Symwave which deals with firewire technology (among other things) announced today the fastest firewire yet.
It's called FirePHY-1600, and increases the speed of regular FireWire to about 1.6 gigabits per second (Gbps) in theory-ish which is twice as fast as FireWire 800.
The cool thing is that it's all backwards compatible with FireWire 800 and 400. And expect people to call it FireWire 1600 any second now. (don't get too comfy as FW3200 is on it's way already)
The true name of this technology is "IEEE 1394b S1600 Physical Layer (PHY)"
They're sending out samples to companies as I type this :)