The curvature would be the big deal. The mechanisms and hardware would be a piece of cake compared to the custom glass you'd need to roll them up and down.
I remember reading an article on the Duster body design. (probably on Allpar)
One of the BIG hangups was that the designers wanted to have curved side glass. They almost did not pull it off because the curvature had to fit inside the existing door width. Once they solved that, it was a GO. IIRC, it was the first car to have that much curvature in the side glass.
If you can pull it off, I think it would look great. I really like the Duster/Demon body style.
On a similar note, I've wondered if the vent wing window could be eliminated on 67-69 cudas. But why stop there? Flush mount front and rear glass, shave the drip edge, etc.