I have thought about converting my ancient W140 S420! It's not a cream puff and it's not rare so why not? The car runs great but at some point something big will fail. Converting it to EV would be easy and it would then become one of the smoothest and quietest W140's ever. And it's a big car so there's plenty of room for batteries etc.
This is the rear suspension sub frame from a W140. I'd bet there's plenty of room for a Tesla drive train! Two battery pack - One were the fuel tank is now (behind the back seat) and another bigger pack were the engine is. You could run the cables and coolant lines down the trans tunnel. Charge plug were the fuel filler is now. With careful planning the car could look stock from the outside and I'd try to maintain the weight distribution. (Air suspension?)
This is a model 3 drive train. It's a very similar in layout to the W140. Even the mounting points are in a similar position & I'd be using Tesla wheels.
