Indeed, my 6x17 has experienced a bit or warp. But with a maximum aperture of f8 the film plane in focus depth is not too susceptible to slight changes.
However the DUO with a f3.5 lens might very well be. We will see. The body itself is very, very rigid. The standard less so. I think I might add some metal bracing to the standard for good measure.
Anyhow, this is what it looks like with Polaroid back.
My Duo x 7 by
Eirik0304, on Flickr
I remember mentioning it might end up cherry red and black. That was before I unpacked the kit and found I had ordered signal red bellows material, not pewter as I thought I had. Anyhow, the colour is signal red (and black)