The Campagnolo Q/R seatpost binder bolts have existed for a very long time. There are at least 3 different models that are on-topic for the CR list, plus some others that would be off-topic.
The first two models were launched around 1960 (plus or minus 5 years). Both used a clip design (back in vogue with modern frames today!). The one had the Q/R lever integrated into the clip from above, whereas the other had the skewer just like a hub Q/R. Both of these were mainly used for the folding bikes that were all the rage in Italy in the 60's. I believe these were the main market for these. In the late 60's, a lighterweight version was developed that was made in such a way that it could readily be substituted for almost any regular binder bolt. I truly doubt that they were ever used as standard issue on any large scale lightweight bicycle however, as they were obviously more costly and there is no logic in using one for 99.99% of all bike riders, as once the saddle height is set properly, you needn't adjust it again.
The folding bikes were however another question as the bikes were marketed to those who wanted to be able to pack them in a small space, and lowering the saddle created a definite volume improvement.
Personally, I fitted one in 1981 or 1982 at the stoker's position of my tandem (along with a lady's saddle) while at University as I was always riding with different stokers and the Q/R allowed for immediate adjustment to suit the newest companion.
I have seen a few up for sale on ebay, but they have never sold that well, so they are apparently not overly sought after.
Steven Maasland
Moorestown, NJ