6'4" here, 6' 8" in my favorite (ok, only, but they're still dead sexy and I love them) pair of heels. I *thought* I would have problems passing because of it, so I've been working extra hard on things I can change... makeup, voice, mannerisms, walking, etc. When I've got it all together, I don't seem to have any problem. Still slip with the voice occasionally, but I still get treated like a lady (for the most part).
Much love for all the tall sisters out there... and for the not-so-tall. Latch on to your inner woman (she's in there, or you wouldn't be posting here!) and do your best. And, please, find people to go out with. I don't recommend going solo your first time or three out, but it is important to get out... you will find, I think, the world is much more accepting than you have let yourself believe.
*hug*