Now this is my kind of doubleneck. From 1982, it’s an Aria Pro II ST-1504FL Super Twin with 6-string guitar neck and a fretless bass neck. It’s Japanese-made, of course, almost certainly from the now legendary Matsumoku factory – note the trademark through-neck stylings so typical of both the period AND Matsumoku, and in this case it’s a double through neck!
It ticks all the boxes for me as a bassist who prefers playing fretless and also dabbles a little in guitar. Also it has the necks the correct way around with the bass neck at the bottom and the guitar neck up top. (Correct way? I explain more about this here, and in case you haven’t been following I did indeed get that custom doubleneck built).