This whole hippster movement began long after I started riding and racing. I began riding fixed gears in the 1970's. I raced track and had a dedicated track bike, a Schwinn Paramount P14. I converted road bikes into road going fixed gears with lower gearing (60-65 gear inches), brakes, water bottle cages and even fenders and generator lights for winter training to get my leg speed back after a season of big gear mashing in road races and TTs. It was real easy to convert the old road bikes into fixed gears, because the rear dropout spacing was the same 120mm as a track frame, and the freewheel threads were the same as a track cog. You could even use a left side bottom bracket lock ring as a cog lockring. The chainline worked out if you placed the chain on the inside crank chainring. Today, I still race track on a pure track bike, and ride a separate road fixed gear for training as well as just running around town. I pull track stands at traffic lights, and all the kiddos are impressed, but don't do all that stupid skidding and stunt stuff.
Note: Due to errors on this webpage, I am unable to upload photos of my steed.