I don't know how I feel about 16mm sized sensor. It's not just a little but smaller, it's a LOT smaller. Here's my GH1 compared to my Beaulieu. It's like point and shoot size:

Note too that the Beaulieu body is being propped up in front of the GH1 and as a result, is closer to the lens. So, it's actually even a tiny bit smaller in comparison.
Most of my first jobs in the film industry where shot in 16mm. I own a Beaulieu and a Bolex but they haven't seen film running through them in over 15 years. I sold all my C-mount lenses too so they are really just completely useless to me at this point. Anyway, I remember the first time I shot 35mm film. It was a stop-motion animated shot for commercial. It was stunning. Even though it had been transferred to SD video, you could easily see the difference between 16mm. There was just so much more detail and color. Even on video! Now a days 16mm stock is so much more advanced. A friend of mine shot a bright eyes video with some of this newer stock and I really couldn't tell that it was shot on 16mm. So, I don't know. I mean, obviously possible to get amazing looking footage out of smaller cameras ("Beast of the Souther Wild" and "Moonrise Kingdom" just recently) but I just don't know...
[edit] Sorry for the crappy iPhone photo.