I think it's incredibly lame and unfair to say that just because she has a straight up and down body she has a "boy body." If that's how you feel then I think you need to go and look at some boy's bodies, because she obviously has a woman's body. The only difference with her is that she's not curvy --- big deal. I was not blessed with huge hips and breasts either but I still have a woman's body. I hate that whole idea because it goes right back to why women are so insecure with themselves and why they feel they need tons of plastic surgery. Real women's bodies come in all different shapes and sizes.
Personally I could see Cat doing it easy because she has great natural looking breasts and what more do you need when you're selling bras? (Except a beautiful face which she also has.) The only reason why I wouldn't want to see her doing VS is because I think VS's whole campaign is really cheap looking nowadays. It would completely kill her HF career and she'd become a goofy overly tanned, highlighted commercial girl.