The auction from 2016 did cough up the only known example.
It belonged to Carl Swanstrom, a prolific collector of tin toys, antique radios, steam engines, and a plethora of other engineering oddities... even a Theramin or two.
12 years ago Carl had a gas bottle filled with an accurate copy of street gas (illuminating gas) and with it filmed and published the only YouTube video of a Paradox gas engine running. For the next 6 years it remained the only one published until our own CrazyDoug published one of his running at Coolspring. The Illuminating gas that Carl had blended was 70% hydrogen, 20% methane, and 10% carbon monoxide.
I advised his widow to turn over the collections to appropriate and reputable auctioneers and I provided names and contact info for a few. I advised her not to let in any "pickers" who claimed to be his friend as they will most likely try to pick the best items at bargain prices. I spoke with her 1-2 years after Carl passed. She said one fellow came in and bought a few items, came back and and bought more. When he came back a 3rd time she finally told him no more and she told me she finally figured out he was doing exactly as I had predicted.
About 3-4 years after his passing, I tried to reach her and a search found she had also passed by then. It was his children who chose the lousy auction service. I don't believe they ever had the benefit of knowing the names of auctioneers I had passed on to her.
Back to the vinyl base Jensen. It was a great buy for Paul, as were several other very rare Jensens. The auctioneer did a horrible job. He was putting 2-4 engines of different brands together and selling them as lots or box lots. None were truly described properly. There were other odd lots that may have included an engine, and a couple completely unrelated toys or parts. If memory serves me, I believe it was Wayne Yoder who ran the auction. I did not bid on anything as the holidays were approaching rapidly and I thought the prices would be high.
To say the least..... That was a tactical error on my part.
Here are Carl's videos of the Paradox Gas Engine.
https://youtu.be/GryagG9Fme0https://youtu.be/1W4cEwqV62g
