There is a bike co-op shop in nearby Toronto, just a block or 2 SE of Spadina. I only saw it just as they were closing up for the day, though.
As far as starting a co-op, though-you need to be in a town of hard-core commuter cyclists for it to work. Where I live, most of the adults that commute by bike only do so because of poverty. $20 used bikes are plentiful here, so the idea of a co-op is probably pointless in my town.