I saw Marie's and Louis's wax head replicas when I visited Madame Tussaud's a few years ago (yes, they are still on display!). They are in the museum's "Chamber of Horror" downstairs (If I remember correctly, this is what they call it). The story goes is that Madame Tussaud was called in and ordered to make the death masks, and these wax heads were then made from the original death masks. I have a picture of them somewhere that I took myself at the museum, so if I remember, I can post it later.... They are not so pleasant to look at, but like apaltine says, not really gory, and interesting.