She indicated that she's been approached by/with regard to Playboy on a few occassions but declined as she didn't want to offend her family (her mother nearly killed her for appearing in a bikini on a magazine cover when she started out.

). Not sure what she's say now that she's doing topless/implied nude.
Playboy definitely doesn't carry the same kind of weight that they used to. And it would depend if she came in as a celebrity pictorial or if she came in as playmate, cybergirl, or just as a model. I doubt she could do a "celebrity" pictorial as popular as she is on the web and car show community. She just wouldn't have enough name recognition in the E!, Entertainment Tonight, Access Hollywood culture.
So she would probably be brought in as playmate, cybergirl or a playboy model. Playboy basically owns a model's ass for at least 3 years if she becomes a playmate. There is a little bit more leeway if you are a cybergirl or a model. And Playboy does not pay as much as you would think to be in the magazine. If a model wants to capitalize on being in Playboy, she really has to network and do a lot of "non" modeling things because playboy usually controls any sort of modeling content that the model does over the 3 years after she appears in the magazine. And often times, during those shoots models will shoot tons of content that does not appear immediately in the magazine or website. Since Playboy owns the content they can choose when to release it.
So if Christine were to shoot some stuff today for Playboy. They would probably shoot hundreds to potentially thousands of pictures. Playboy could still be releasing stuff from that shoot as far as 5-7 years (in some cases even decades later) after they did the shoot. And Christine won't see any additional money for that, since Playboy pays a flat fee up front from that initial photo shoot. Or they could reuse the content as well in the special edition magazines or features on their website. Playboy can do whatever they want with it since they own the images.
In the modeling world, models very very rarely get any sort of residuals for any of their shoots. Usually it's always up front as one time payment. That's probably why many models do so many photo shoots.