I hadn't, until I came across this report.
Porsche drivers do not generally have mud under their fingernails or ruddy complexions - but this month a special breed of the aficionados mark a 50th anniversary. It was half a century ago that the last Porsche tractor was made.
In a significant change of direction, the Stuttgart-based company stopped making its tractors in 1963 - the same year it started production of its now legendary 911 sports car.
Yet the 120-horsepower two-cylinder bright red tractors with the distinctive engine cover had by this time built up a loyal customer base for the great performance they consistently demonstrated.
. . .
Restored examples can now fetch up to €18,000 [about US $23,600], the Frankfurter Rundschau newspaper said on Wednesday, but even bashed up ones are still worth a lot - and their value is rising.
There's more at the link, plus a photo gallery of images. There's also an enthusiasts' Web site about them, and a number of videos of vintage Porsche tractors on YouTube. Here's one example.
I can't help but feel a little disappointed. I mean, I'm sure it's a perfectly adequate tractor . . . but being a Porsche, why isn't it plowing at a hundred miles an hour?