[JCavilia]

I've never seen an analysis, but I strongly suspect that height provides no advantage, but not necessarily any large disadvantage.

Power-to-weight ratio is only one parameter that's meaningful. It's most important in climbing, but matters less for time-trial specialists, roleurs and sprinters. Absolute power, aerobic efficiency (VO2 max), recovery ability and many other factors matter.

Although there's a range of sizes in the pro peleton, my impression is that pro cyclists are on the small end of average. They are certainly shorter on average than pros in sports where height really matters (baseball, football, even soccer).

The tallest Tour de France winner was Bradley Wiggins at 6'3" last year; tallest previous winner was Miguel Indurain at 6'2". They'd be little guys in many other pro sports. Armstrong is about 5'10", same for Contador, Merckx a hair over 6'.

 

[JCavilia]

I ride primarily on a very speed-friendly course (a paved 4 mile loop, no climbs, no lights, few cars - not even a sharp turn to slow you down). Everyone there is doing intervals or a pace line or otherwise trying to go very very fast.

Barring the occasional exception, it's my observation that the fastest guys around that course are the 6'+ giants with hams for thighs.

Roleurs. Muscular guys with great power-to-drag ratio. The biggest pro cyclist I ever heard of, Magnus Backstedt, was 6'4" and 210 pounds. He pulled some trains in his time. But he didn't climb mountains very fast.