OK, I know in saying this I am ageing myself, but at least patballard is my peer. How many of you were shooting films during the Spiratone days? Well, I sold my whole studio equipment of all format when I quit in the late 90's to travel and teach. I used to have one of those as a photo correspondent.
You know what gadget I'm talking about. The quality suffers, but it's good enough for editorials. It's a little mirror that enables you to point in the direction 45 degree from your target, so they don't think you are shooting at them. It worked really well. The thing is to find if someone has renewed on this gadget and took over the patent.
Also, not sure if this will work over a digital lens.

yes, if you're able to find an old Photo magazine of the 80's , you'll see a Spiratone ad, and the catalogue.

Wow, good detective work, cc.
Yes, it looks like one of them. they have different model. I suppose the better mirrors are more expensive so you get less aberrations in the reflected image.
yes,  although i think it was like 5 bucks brand new.

this one is also a bit boxy, there was one that is smaller and compact much like a microscope .