I will second what Mel wrote about "the further one strays from the average height, the better a technician he must be" (paraphrase). I'm the same height as Baryshnikov, but I haven't received any phone calls from ABT yet :shrug:
Seriously though, unless one is a star or otherwise necessary to the company in some way, one pretty much needs to be able to partner a range of heights, and tall men can do that more easily than short men. Of course, there are the odd times when one is paired with a taller woman, but the result isn't usually pleasant for anyone