All the same, you should be careful about using deductive reasoning in this way. You're assuming that the only criteria upon which you were measured were formal education and experience with big clients, but what about how you struck them emotionally? Did you have that trustworthy/hardworking/whatever air about you that perhaps some of your colleagues had? Did your mode of dress impress them as much as for other candidates? Had the interviewer seen one-too-many people with the exact same qualifications as you, and thus was looking for a little something more that he didn't search for with the other hires before he got desensitized?

I'm not saying that it WASN'T height discrimination; I'm just saying that you should be careful about concluding such things so easily.