I know that if she tries boot cut jeans with a tank top that she can pull down over the top of her jeans then that should do it. That's pretty much all I could wear before my body surpassed the crazy adolescense stage. Or dresses that go about mid-thigh.
Note: this should all depend on where her torso curves are and how high up
longer tops should do the trick, I get these tank tops at old navy to put under shirts since most shirts are shorts on me, I'm 5'10 and can pull them down over my butt if I wanted to so they should definitely be long enough to elongate her torso, dresses are another option. sounds like she's lucky to have a guy that cares so much, on all the makeover shows they try to make peoples torsos shorter and legs longer so she should be proud :)
I have very long legs and a short torso. my torso is really short its only the size of my stretched out hand! It doesn't bother me at all I don't know why your girlfriend would be insecure about it. if anything it's a good thing, I think I'd rather have my short torso/long legs and short legs and a long torso that would be kinda weird.'
she could wear long shirts, tunics, stay away from high waists, wide leg pants
I have the same problem and I just do what SPINALITTLEFASTER said. That's pretty much all I wear. And the other answer was right, I know girls who are extremely unhappy with short legs and would kill for long legs so embrace who you are!
I guess she should avoid skinny jeans (b/c they make your legs seem even longer) and short tops.
Longer tops will also make your torso seem more in proportion to her legs
PS tell her to be proud of her long legs! I know girls who would kill to have longer legs