It seems quite easy to find old folders for different formats with for example a Rapid Rectiliniear / aplanat with a focal length of 105 mm or 125 mm. Would it be out of the question for these to cover 4x5? I am of course not after corner sharpness. Far from it! I would like them to fuzzy up a lot. But I don't want total vignetting and a circular image.
I tried to calculate different image circles based on an angle of 50 degrees and ended up with one meter of coverage. Obviously I don't understand this math very well...
Dialytes seems to be quite common in these folders too.
I could of course just buy one and try it out and crop the picture if I don't get what I want. But I suppose one or two here have tried this, no?