The wonderful world of Barbie?

I am in a place of having to decide what to do about the barbies in our home. First of all, I have never bought a barbie for my kids, and have been pretty set about Julia not having one. Yes, I grew up with barbies...lots of them. I spent many hours changing their clothes, doing their hair, building houses and such and also having them engage in sexual acts together. With just one Ken he was a very lucky man! This is just one of the reasons I did not want to enter into the world of barbie with my kids. The whole body image issue is another huge reason which is pretty self explanitory.
When Julia got a couple of barbie movies for her birthday a couple of years ago I gave in and decided that was okay. In fact, besides being utterly annoying the movies usually have some good message behind them. She has checked out books from the library and we have read them together. One of them in fact made me tear up. It was a very good story.
However, Barbie the doll has entered the house over the past year. The first two that she got I thought well, okay, maybe it won't be so bad. After finding my 3 year old son (at the time) undressing them constantly I decided to put them away. They somehow got lost in the move!
Well, Barbie is back. We now have at least 7 beautifully shaped blond haired beauty queens that grace our home with their naked bodies.
Julia is good about putting clothes on them. She does not have a Ken doll so she pretends one is a boy and they kiss the night away. I ask her what she likes about Barbie the only answer is "she is pretty." I have tried to talk with her about inner beauty vs. outer beauty. She gets it a little I think.
Yet, still all barbie knows how to do is fall in love and kiss.
Then comes my other delima. My son. Now 4, he is still infatuated with Barbie. He states he loves her and wants to play with her. Unfortunately, or maybe not unfortunately, he only wants play with her naked. He hides with her in his bed, he hides her with him upstairs, he tried to take her to school today, all while she is bearing her perfect melons and nice hind end.
So, what do I do?
If it was up to me they would all go in the trash. My daughter begs to keep them. I have asked that they be kept clothed, but this isn't happening. This is why Harrison is hiding her.
As a parent we make lots of decisions. Some are easy some are hard. I know this seems silly to some, but it is something I have to make a decision about. It is one that I want to do the right thing.
I would love some input. I would love some wisdom. If anyone has any please share.