I don't really have childhood memories of being in the wrong body, but looking back, I can clearly see some trans* stuff there.
Untill puberty and highschool, gender didn't really exist to me. I felt different than the other girls, but I didn't really feel like being in the wrong body back then. (that happened after puberty started)
Back in the childhood days, I played with a lot of 'boys' stuff. Space lego, playmobil with indians, cars... I hated dolls and barbies. I had way more guy friends than girl friends. At some games on school during breaks and such, girls weren't allowed to play along. Except me. I was not seen as a boy by the other boys, but still I was the only 'girl' that was allowed to play along.
My mother told me a couple of years ago that as a child, I was behaving just like a boy. (but still looked like a girl in girly clothes -girl pants and shirts, I didn't wear much dresses because they were unpractical- and long hair)