If your girl is good enough to need tail rocker on a powder day.. couldn't she pick out her own skis?
If your thinking that's what is best for her, I disagree.
I have both the tstw and the JJ and for higher speeds in choppy snow, I actually prefer the tstw. One thing to think about is women do have a tendency to sit back a little more. On a heavily rockered tail for a powder ski, females sit back even more and they are actually more difficult to control. Of course this is something you get better at over time. But like I said, if your lady can't pick out her own ski, she probably isn't going to benefit at all from a rockered tail and likely will make the ski more difficult for her to get comfortable on.
I'm 5'7" 120lbs and on a 175 JJ/ 174 TSTw. I love them both.
But... if a rockered tail is a must. the k2 Missbehaved skis really long and the 159 would be a great size for your lady. It's pretty stable and turns well, but I'd say my TSTws work better on the crud.
The one ski I do want to try though that fits your specs for the most part is the Moment Bella.
Final word.... you do know that chicks ski on men's skis all the time right? Some of my favorite skis have been "men's" skis. Salomon Shogun and Lord (although they made a women's after) the JJ (mine are mens). I was on Ar5's for a few years. They Caylors are super fun. Soooo why not the 161 jeffery?