Yes, the turrets that have been discussed here are in their catalogs also called bed turrets. Logan also sold a tailstock turret but as Jim opined, probably didn't make it. Atlas sold a similar one but also probably didn't make it (could have, judging by the photograph, been the same one). It is a lighter turret mounted to a 2MT arbor, and could be mounted in the standard tailstock ram. I have one, and it takes 5/8" shank diameter tooling. But Atlas also sold a dedicated tailstock turret that was heavier and was lever operated, with six adjustable stop screws on the back end. It takes either 3/4" or 1" tooling.
Back to the bed turrets, they are advanced by a long handled wheel (capstan wheel??) that drives a gear that engages the carriage drive rack. A 1953 Logan catalog says that the same turret model number was used on the 10", 11" and 12" lathes. I assume that you had to specify which lathe when you ordered it, as the turret height would have had to change to match the lathes. If the 10" bed turret is still being considered, I would figure out what model it is and call Logan and find out what part has to change in order to convert it to 11". Atlas, if they no longer supply a part but still have the drawing, will email you a copy if you ask nicely. I haven't heard that Logan would do the same. But it wouldn't hurt to ask.