I bought a Buick Roadmaster new in 1992 and kept it until I got my Model S in 2016. It was a great car. Very reliable. My mechanic wanted to buy it from me, but unfortunately the car outlasted him. He died of a heart attack about 2 years before I was ready to sell the car.
When I got my Model S, people were talking about how much bigger it was than other cars they had driven. The wheel base is the same between the Roadmaster and Model S. The width is the same too. The only difference was the Roadmaster was somewhat longer. So I have a bit more room in the garage.
I though it would be cool to take the skateboard from a Model S and drop the chassis from the Roadmaster on it. I don't have the skill or the tools to do it though. I liked the Roadmaster interior better.
Look for the Plaidessey from the Boostedboiz:
You can live vicariously through their lives, as they dropped a minivan shell on top of a model S Plaid "underbody".