Retrotec got its start in single speeding. Bob was a huge fan and promoted it whenever he could. Bob put on the first WHIRLED race in 1995. I have tried to continue that legacy by helping SSWC whenever I can.
We can build any style of Retrotec or Inglis into a single speed. We prefer to use Paragon rockers or sliders for taking up the slack. As most people seem incapable of riding a hard tail on dirt anymore, why not really blow their minds with how useful a hardtail single speed can be?