She's always had a fuller, curvy, but very slender, womanly figure. I totally fell for her in one of Wheadon's Firefly episodes. I'm going to guess that she's natural.
Titfuck, buttfuck, pussy fuck... hell, I'd be satisfied at this point with a simple lingerie non-nude photoshoot that produced some hot poses for us! This girl is really holding out long, whereas most actresses have already released a sex tape by now.
Which brings up a second thought... would a Christina Hendricks sex tape be worth watching? On the one hand it's Christina Hendricks, but on the other it's with that nerd boy husband.