I don't know how common it is, but I'm a cross-dressing heterosexual transman. I love wearing skirts, feminine jewelry, dresses, and so on, although I mostly just cross-dress at home so I don't have to deal with people thinking I'm a woman. Some would consider me bi since I'm fine with trans women who haven't started on transitioning yet, but eh. I just see them as women, no matter what their body looks like.