Yeah, Sheldon Brown is right. There is no effect for leverage, BUT rather how your body/legs fit into the frame geomerty. I am a typical Japanese long body-short leg rider, and I DO like 165mm. Also I remember, in general, FIXED gear rider seems use shorter cranks, the RPM vs Torque is another concern. Also, if you have lower B/B, and very short wheelbase, the shorter cranks works better for turning corners, and not touching front wheel.
KEN TODA, I do not mind to have 160mm crankset, I vote for less is better!