Three guys even set off on fixies, but only one is still in the race at the moment.
"...and yeah, this fixie thing, um, it's pretty bomber"- Matt Chester
You can find out more about the race at the official Great Divide Race website and follow the race on the Great Divide Race Blog. There's a thread on the MTBR forum discussing the race and equipment, with a post by Matt Chester explaining why he had to quit the race.
The fixed gear bikes being ridden my Matt Chester and Rudi Nadler are similar to the set-up I'm going to go for on my SSUK prize frame from Solitude Cycles.