From ca. 1954 - the Linex stereo camera. First marketed by the Lionel Corp., of model train fame, in 1954 and dropped in 1955. It was sold as a bundle with the camera, carrying case, carrying strap, film cartridge & stereo viewer. It used a custom 16mm film cartridge which the user would mail into Lionel. They would develop and return the film with a new cartridge included as part of the development cost. The set I found (on ShopGoodwill) was complete including the original box with one empty and one unused film cartridge.
Story is Joshua Lionel Cohen, the president of the Lionel Company was given a StereoRealist for Christmas but found it too complicated so he directed his company to develop a simple point and shoot stereo camera. They sold approx. 85,000 kits and was then dropped by Lionel, ostensibly for low of sales. The web sites I read this story on (possibly quoting each other) thought 85,000 unit was a decent sales volume and couldn't reconcile the seeming disconnect.
However, while surfing online & reading up about the camera I stumbled accross an old lawsuit, Julius Lakoff v. Lionel Corporation, which alleges Lakoff was actually the inventor of the camera. Supposedly, he gave his design to a patent attorney, John M. Cole, who also represented Lionel and who in turn passed the design to Lionel instead filing with the patent office. Lakoff then sued Lionel and the attorney Cole for infringement & damages.
I haven't found the complete case history but in a ruling from Jan 1955 the judge ruled Lionels request to dismiss was insufficient and was allowing the case to proceed. Quoting - "The motion to strike the affirmative defenses and to dismiss the counterclaim is granted, with leave to defendants to serve an amended answer as to the defenses within ten days after service of the order to be entered hereon with notice of entry thereof." So Lionels defense was shot down.
My supposition, with this minimal evidence, is Lionel either lost or decided to settle and had to pull the camera from the market in 1955 as a result.