I've used a 6.5cm x 9cm sheet film camera. I think it's the smallest sheet film you can buy. I started shooting it because it was fun, the camera was free and I could buy cheap film from JandC. It has a great lens on it and the portraits I shot turned out pretty good.
I guess it was a novelty but worth the time and effort. I still have film in the freezer so it remains an option when the mood strikes.