Lots of us live closeted lives before we come out to other people, and we do it even after we've come out to those who are close to us. I'm not sure if those situations really fit what you're asking. For a long time, the only one who knew I identified as male was my then-partner. I thought of myself as a cross dresser because I didn't want to be a transsexual. When I started seeing myself as transgender, I sometimes identified myself as a cross dresser rather than trans.
I had different modes. In my head, I lived other lives as a boy. In the real world, I had short hair and wore men's clothing but just looked like a masculine girl for a long time. Every once in a while, I would spook someone in the women's restroom, but it didn't become a problem till I was actively identifying as transgender. Once I realized that there were real people out there like me--not just obscure case studies in some book--I guess that made a big difference. And I now knew that I wasn't crazy. I started to let myself get more comfortable with my masculinity, and that's when people started hassling me.
This went on for years, and then I was less and less able to deal with being trans. In grad school, I went back in the closet. That was definitely some kind of stealth mode, but I can't call it active stealth. I didn't tell myself, "I'm a man, but I'm going to live as a woman." Rather, I tried to blot out all the transness and deny that it existed. I had been getting to close to the truth for a long time, and when I was on the verge of seeing it, I recloseted myself. Whenever I did do some self-reflection, I still thought of myself as a woman who wanted to be a man, or as a masculine woman. Anything but the truth. I couldn't take steps to transition until something inside me snapped and I realized that I really was a gay man, not a woman who wanted to be a gay man.
So, I came out to myself in 1988. I lived varying degrees of "stealth as a woman" until 2008. If you're looking for a great way to mess yourself up, I definitely recommend my route.
But I always wanted to transition, and I planned to do it...someday.