Second of all, check out this article on Transgender, a topic that's really new for me and that I didn't really articulate anything about in the earlier post.
Thirdly, from what I HAVE read on the issue of gender reassignment (sex change), it seems that mimah nafshach there could be the real possibility of a female-turned-male marrying a male-turned-female halakhically. The ceremony would probably look pretty darn interesting.
Finally, I'm going to go to hell for this, but I can't resist: If such a shidduch would work out we could say:
מצא מין את מינו