Check out this acoustic 7 on Reverb

[MIL8]

https://reverb.com/item/32269520-laplante-martin-7-string-ooo-1994

I've never seen one before, sure thought it was interesting. I'd love to play it.

 

[M3CHK1LLA]

kind of a strange shape, but im guessing it needs to be that way to support the stress of an extra string.

 

[MIL8]

It probably looks that way because the neck joint is at the 12th fret, which is how the first Dreadnoughts were done. Makes upper fret access difficult but adds to the sound.

 

[ElRay]

Right now, there's a whole bunch of "Doff" Russian 7-strings on Reverb. Most are Nylon (as expected), but some are also steel-string. As for "weird shape", there's a jumbo with a shape I've never seen before:

 

[MIL8]

That is certainly odd. Wonder how it sounds?

 

[ElRay]

That is certainly odd. Wonder how it sounds?

I've done some digging. It's supposed to be better sounding with the lower notes in the "Russian Tuning" (hence it being a "jumbo"). Digging into the repertoire, I see that the low D2 is sometimes dropped to C2. Also, it seems that that shape is semi-traditional. It would be at the top of my "Next Acoustic" list, but I'd rather it be a nylon stringed guitar.

As an interesting aside, it's "proper technique" to play with the thumb fretting the 7th string. It's amusing to watch "Classically Trained" guitarists play by switching between thumb-over and thumb-behind playing. In all the videos I've seen, they telegraph the switch to thumb-over. It's like it takes some serious mental preparation to "do things the wrong way"