"I also know that S&W dallied with the 30 Carbine but quickly gave up on it."
Not so much that S&W gave up on it, but the military decided the idea of a revolver chambered in .30 Carbine served no practical combat purpose. Of course, it is practical to chamber a revolver in .30 Carbine - Ruger has done it for years with their Blackhawk. There was also once a semiauto pistol chambered in .30 Carbine, but I can't remember the name - started with a "K" I think. It was not a success, as there were some instances of the slide blowing off.