Damn, there are so many, but two immediately come to mind.
The first is actress Rooney Mara (The Girl with the Dragon Tattoo 2011) who I find insanely beautiful. She comes off as very reserved and demure, but she has no problem getting naked for nude scenes. I'd love to see her letting lose and getting wild for real. Sometimes the quiet, "proper" ones can be a real surprise.
The other is Taylor Swift. Some can't stand her, but I think she's gorgeous and super cute and I love her tall, thin, fit body. She's a brilliant marketer and comes off as very wholesome and sweet, never really relying on pure sex appeal or "exploitation." So, for that reason, I'd love to see her in some ultra-hard core crazy freak show fuck fest where she's getting fucked and blowing dudes like there's no tomorrow. DP, double anal, blow bang/gang bang and loving every second of it. A complete contrast to the persona that everyone sees all the time.