speed & stature
 

Given equal amounts of fitness, age and cardio efficiency should a taller or longer legged person be able to maintain a higher cadence or speed?

Depends how fast they can pedal.

It makes no difference except you will find that professionals who are short can climb mountains and long legs mean you can sprint. In the real world though---

Higher cadence for how long?

I gather that in the world of pro bike racing, short LIGHT riders climb well and tall BIG POWERFULL men sprint well. I don't think that cadence or speed (over some undefined distance) is the important factor but rather watts and power vs load for a given task.

You've got guys like Heras at 125 pounds or so who could fly up mountains. And then sometimes big guys with big engines, such as Ulrich, also climb pretty darn well and aren't such great sprinters. Glad I don't have to figure all this out.

believe it is a mixture of your muscle fibers, fast twitch verses slow twitch. they can be trained on which one your lacking the most power in.
I do find that those that seem to have a longer femur seem to do better in climbing than sprinting just an personal observation

Power to weight ratio drives much of it. Increasing power comes from genetics and training. The other factor is mental, how much pain can you take. When you put it all together you get a pro cyclist.

Lance Armstrong was 5 foot 10 inches and typically competed between 165 and 170 pounds. He destroyed the competition in the time trials and in the mountains. It is all about the power to weight ratio at lactate threshold. He had the highest. If you have not seen it, here is Armstrong destroying the field climbing Alpe d'Huez in the 2001 TdF giving Ullrich the "Look". I only wish I could stand up that long climbing at ANY speed.

http://www.youtube.com/watch?v=GHJErrp4eOw