I'm 5'4" and I wouldn't be happy if tall men started wearing heels, because I probably wouldn't be able to look them in the eye comfortably. And from knowing several tall men, somewhere around 6'4" to 6'6" door frames, low hanging branches, etc become a big hazard, so I don't imagine they'd want to wear them regularly anyway. But I have to say, I've seen some men in heels and they looked good.
Julie