NGL, that sounds cool as fuck. Just imagine 20 layers deep caskets and the bottoms one have started to get crushed by the weight. The bottom layer is just splinteres, both bone and wood, and if they're happened to be anything left that hasn't rotted away by now it's been squeezed out by all the pressure. This process happens continously as time goes on, given just enough time before caskets for the bottom layer to get pushed further and further down.
Sure there's the practical problems, but again that sounds cool as fuck.