Hmm...
Well my sister is a butch, and she's currently asexual, but she has
made it pretty clear to me that although at times she wanted to be
a guy, so she could learn things like Kickboxing and all those male
activites, she told me that she never ever considered the option of
going for a sex change.
It'd be pretty cool if she turned out to be FTM though. My sister
becomes my brother, and her brother becomes her sister. But then
again...my Dad would probably blame it on me for giving her the
idea. 
Ahh, whatever. One transsexual is enough for my family.