Simplex Dropouts
 

Did Simplex ever make a driveline side dropout without a derailleur hanger?

Yes, Simplex introduced the hangerless 881/881B rear dropout set circa 1962. They remained in production into the late 1970s. They were a topic of discussion in a very recent thread.
https://cimg6.ibsrv.net/gimg/bikefor...3776069536.jpg

Yes, and would that all vintage French bikes come with them, so the owner could use any derailleur without resorting to any of the various work-arounds necessitated by the integral-Simplex-hanger versions.

Fair enough especially since quality simplex rear derailleurs are getting harder to find (and as you point out in your website there are other derailleurs that can work without a stop if you thread it). But the later stronglight drop outs were threaded and had a stop so you could run pretty much anything you want on them.

https://cimg8.ibsrv.net/gimg/bikefor...f74b63def5.jpg

And don't forget the rare Hurex dropout.

https://cimg8.ibsrv.net/gimg/bikefor...58a91b2004.jpg
John D. Thompson, inventor

OOOhhh! I want one of them with a Campy RD! ;)

https://live.staticflickr.com/6146/6...64cd5de3_h.jpgCinelli_Model_B 095 by iabisdb, on Flickr

Thanks all. I think the one I’m looking at has had the hanger lopped off.

Welcome to the club. :)

The 881 dropout T-Mar speaks of was a predecessor of the later dropout that was ubiquitous on bikes like the Peugeot PX-10. Though it was drop forged, it was thinner than the later dropouts, 5 mm thick rather than 7. Even later, Simplex made dropouts (maybe only the short type in photos above, but perhaps also the long type) having a "Campagnolo" style derailleur hanger (compatible with Campy, Shimano, Suntour, etc.) rather than the proprietary one for a Simplex derailleur. I like the 881 dropout, myself.