My first car when I was 16 was a Sunbeam Alpine. I had a tonneau and used it. Kept the rain out when the car was parked.

The price you mention for the Box tonneau as an option sounds right - very expensive. In 6 years I have only seen 1 car that had it as a factory option.

When Porsche got rid of it a few years ago I picked one up for $45, new in the box. Still in the box.

Pic from Tom S. I put my humps on his tonneau a few years ago and took pics but I cannot find them.