I'm usually awful at visualisation, but that's pretty much how I expected it from drawings :/. Anyway,
size comparison of 2g/3g/4g from various angles.
Easier to fit in an empty jeans pocket, harder to fit in a half full one. Perhaps easier to hold while vertical, but more awkward while horizontal. That much is testable with 5 minutes cutting up wood. As for
curviness, 3g seems like 1g; 4g seems like exaggerated 2g. I prefer the 1g/3g style; I was thinking these give a better grip but given that hands and fingers mould around the edges I might have to limit it to an aesthetic preference.
Why can't anyone take a nice focused High Quality picture of these things when they see em.
Thoughts:
1. If you're taking a sneaky pic, you try to be as quick and subtle as possible.
2. Apply a filter to reduce chances of identifying marks. Not just against serial numbers/unique unit blemishes but perhaps against any watermarks the camera puts on the picture directly (aside from easily removable EXIF). I'm guessing that if printer manufacturers do the sneaky thing with the yellow ink so you can trace a printout back to a printer, so might camera builders?
A basic encoding of a 10-digit decimal serial number, say, would require colouring only ceil(34/8)=5 bits. Better algorithms adjusting more of the picture could be made resistant to common filters (and JPEG fuzzing!).
One low tech approach to deniability would be to get a friend to take a photo of the photo.
3. Add to the mystery.