Years ago I nearly bought an old musty looking large rectangular sound box
fitted with several groups of short six string permanently tuned open chords.

Each set of 6 strings was equipped with a bridge and some kind of tuning pegs
[probably similar to autoharp pegs, sorry I can't remember]

I don't think it was a home made 'one-off',
I researched it at he time and have vague memories
that it might have been a fairly rare short lived unsucsessful commercial factory product.

I lost contact with the ebay seller, so failed to buy it.
Now I can't remember what it was called or find any trace of any similar instrument on the internet.
I've also lost the digital photos so can't be too sure of the dimensions
and string lengths to reproduce a similar crude acoustic box strummer.

But it would be a very interesting 'build' project,
especially if each individual chord was fitted with a cheap nasty ceramic humbucker
and the entire weird contraption was plugged into a fuzz box.