That's a lot to hope for; I'm sure we'd all settle for just topless, even. But then, a bottomless girl wearing a t-shirt has always been a HUGE turn-on for me, so I'd settle for either.
There was a clip of Lucy Pinder on some TV show, it showed up in a thread a few weeks back and got me thinking. Someone who I believe represented Lucy was saying in the video that she'd been in the public eye for a while now without going all-out topless yet. She said they'd done it to increase demand (like Lucas holding out on the Star Wars DVDs this long) and that they'd wait X more months, but no longer than that, because if they teased for too long the public would get bored and not care anymore. Considering the teases we've been given since Christina supposedly came of age, I can't help but think we're going in this direction, but with her you never know. Does anyone really think Christina will ever go nude or even topless, and if so, when?