I myself have used "genetic girl" to differentiate from tgirls. Usually this is used in a context of meditating on some trans community issues.
I do notice many transgirls appending T- CD- TV- to their avatar and handles online. I think this is purely to forewarn other guys of who they are....after having heard so many stories of men who get bent out of shape once they find out what's behind the curtains.
If it was up to me, I would do away with "trans-" and "transgender" altogether. Plain vanilla "girl" is simplicity personified.
As for how insulted guys would feel if someone called them a "she" or a "her" well, in the gay culture, it's quite common to call each other b*tches, girls, and whatnot. And in the mainstream culture, I am increasing seeing girls called each other "guys" and even "dudes." Even a man's man (raised eyebrows) are getting so high maintenance and sensitive these days, I'm shocked nobody has started to call them girls.
I know it's one of those asymmetrical things where girls have more freedom than guys. But I believe language shapes reality and perception. The more people use the standard pronouns interchangeably, (hopefully) there will come a day when people begin to realize that gender is dynamic. Not something written in stone and permanent.