You COULD replace the rear hub for one that is internally geared. It may cost you $200 for the hub and relacing the wheel, but you would get a 7 or 9 speed bike out of the deal. 3 speed internally geared hubs cost quite a bit less. You would also need a shifter and I'm not too sure about how that works with an IGH. The cool side is that you can shift when stopped (not that this will be important in a race). There are some guys in the commuter forum who have done this with a Bianchi San Jose.