I have a few of these Minolta 16 cameras. Looking at the plastic piece that forms the film gate, and the image spacing, it seems that this could be opened up to get a bigger image on film without sprocket holes. The lens FL is longer than the diagonal (17mm diagonal, 23mm lens) so image circle may not be an issue. The image spacing gives what looks like 3 times the clear area compared to a Minox frame, so frame overlap should not be a problem. The galilean viewfinder of the Minox II shows an increased angle of view and may be a perfect match and likely could be put on the I. Maybe use the whole outer case of the II.