Not yet, but I do agree that it would be most useful to have a self tailing end fitted to the drum. On my boat the windlass drum has been used on several occasions for hoisting someone to the masthead, and a self tailing device would provide a further element of safety for that operation.
About two years ago I looked at the various parts that Lofrans could provide, but at the time a self tailing end was not on their list of parts. If Lofrans could provide such a fitting, I’d be one of their first customers to buy one.
There is something known as a “wincher” that it might be possible to add on, but I’ve never seen or used one to know if it would really do the job.
I note Elias, that you keep your boat in Greece. Many years ago on a ship at a repair yard in Scaramanga (sorry if I’ve got the spelling wrong), I remember there were several very capable machine shops located near to that yard. There one could take anything to them and they could manufacture a new part and modified as you wanted it, and do it almost while you waited. If that ship repair yard and those machine shops still exist then I’m sure they could help you to make such a fitting.