"Carbon sequestration" sounds so much better than "Bodies in the basement"

When it comes to unconventional methods of body disposal, I rate for Pierre Giraud's cunning 1801 plan (as described by Philippe Ariès) to turn dead people into glass memorabilia by vitrifying their skeletons:
Also.

No doubt all you cool kids were aware of the Scruggs Screw-thread Coffin right from the start before it was fashionable. As for me, though, I had never heard of it until John Ptak brought it to the attention of the wider world. The Screw-thread Coffin is thirty tons of burrowing, tearing might, powered by a 1000bhp engine using rocket propellant.

A tracked trolley carries the machine to the drill site where it is tilted for almost vertical drilling with its Formula C30/1 drill bit which can cut through any known metal. Chain mounted metal spikes on its side allow for its return to the surface when the rescue is complete. No, wait, that's the Charter Model (special discount for groups of 15 or more). I'll start again.

No doubt all you cool kids were aware of the Scruggs Screw-thread Coffin right from the start before it was fashionable. It is designed to save space in the cemetery by its vertical attitude. It can be inserted by tractor power, or by hand at a pinch. And when the cemetery does eventually run out of room, you simply screw each coffin further into the subsoil to make room for new ones in the same vertical hole, much like the simonists in the 3rd Ditch of the 8th Circle.
The decorative fish or duckie on the top is probably not intended to be functional, but might contribute to a positive ambiance if the graveyard suffers from regular inundations.

Going back to the corpse vitrification project:

In spite of his enthusiasm, Pierre Giraud had some doubts about the fate of his plan, and he offered his own body as a subject of experiment. "I am so convinced of the infinite good that would result from this plan that if it is not carried out before my death, I have proposed in advance ... that I be used as an example. I have asked that my survivors arrange with a soapmaker or surgeon to separate my bones from the rest of my remains, to burn the flesh and fat, and to place the resulting ashes, along with my skeleton, in a tomb that I have had built especially in my garden, until such time as my descendants can have my body converted to glass."

Ariès does not record if Giraud's descendants acquiesced to his wishes, or whether they decided that he was only making a spectacle of himself.

Bonus corpse vitrification: