Is there anything on the market like a hub that looks like a freehub but that doesn't use a freewheeling/ratcheting mechanism? Or is it possible to open up a freewheel and 'fix' it from ratcheting (and if so, how difficult would this be?) What I'm after is a way to build fixed multi-gear bike, so that one wouldn't be able to 'cruise' but would still have an entire cassette of gears available and accessible using a shifter/derailleur.