Technically your not limited to one gear riding fixed. SA has three speed fixed hub that are readily available. That's a boat load of dough to make a fixed or single speed bike in my book. I built like two decent fixed gear bike with that much using newer quality stuff. You could pick up a decent older road bike and convert it. I picked up a nice Schwinn Tempo Columbus tubed frame bike with all 105 components and Cinelli stem and bars for $50. Buy a new wheelset, sprocket and lockring and some tune up type things(tires,tubes,chain, brake cables, bar tape) for about five hundred tops I'd say you'd could easily have a twenty pound or sub twenty pound bike. I guess I'm just not a big fan of new fixed/ss frames. They just seem bmx cruisers with 700c wheels on them. Flat, riser bars, platform pedals with big goofy straps and every color of the rainbow on them. They just seem really cookie cutterish. Sorry for the rant. lol.