You are correct about the parts being available in QBP and such. I was working in an LBS at the time. I suppose the timetable of 'boom' I'm talking about falls in when the generic sealed-bearing Velocity hubs started to show up on the scene. Before that you needed to go the Surly or Suzue Basic route if you wanted a cheap-ish hub. Prices were notably higher in price though.

I know that I was getting into things right around '03, and my friends were all about it by about then too. But it wasn't nearly as regular an occurance to see a fixie rider on the street (in SF/Oakland) until '06 or '07.