Kay as sort of nailed the problem -- while the number of known TGs is relatively small compared to G, L, and B, it actually covers many distinct groups of people. The definition of TG is a reflection more of what one is not (gender is not congruent with the body) rather than what one is. A more positive term is desirable, but there are multiple distinct affirmations to cover, and this seems to necessitate having many terms.
I'm somewhat inclined to support the idea of people simply being women/men/androgyne/whatever. If you happen to be transsexual, that can offer a descriptive detail (and in unpleasant company, you may be forced to provide one), but male/female/androgyne/whatever remains the primary. I don't know if "transsexual woman" is really satisfactory for a MtF, but the last word emphasizes what you want out there, and you can revert to this term when "woman" does not please your audience (without having to include "man" or "male" in it).
Modifiers (may use none or multiple): Transsexual, transgender(ed), trans-, intersexed, crossdressing, androgynous, gay, bisexual, straight, pansexual, asexual, etc...
Base words: Woman, man, androgyne, two-spirit, etc...
Syntax: [Modifier, Modifier, ...] [Base Word]
Example: Androgynous straight man