I'm guessing you didn't see there was a
giveaway raffle for one just last week. Ironically, it began the same day as your post. (It's already ended, too.) These have been discussed a bit over the last year or so. I'll grant they're shaped like a guitar, but they're tuned like a mandolin.
I've had some single-string electrics. What they lose in that jangly sound they make up for in the ability to bend the strings. I'd expect the same would be the case in an acoustic instrument - I suspect less successfully, though.