Here's an interesting link from Surly: 63xc. The title refers to the 63-inch gear you get with a 42-18 or 49-21 gear combination.
A section of the website praises the silence of the fixed gear and the feeling of direct connection the rider gets when riding trails not only with a single speed, but with a fixed drive.
Funny. Back in 1980-81 I was doing that on my commuting fixed gear, cutting through the back ways to get to work from my residential neighborhood. Any time I wanted to ride sub-par surfaces I used the fixed gear, until I built my first 'cross bike on my old Peugeot frame. That was followed by a version on a Trek touring frame, and finally by the excellent Cross Check.
I don't know if I have the kneecaps to push a heavy bike with a 63-inch gear on some of the climbs we have around here. I feel pretty confident that a light bike wouldn't hold up to the pounding of a descent on glacial debris. But I salute their purist sentiments.