Ed - Cirkut film is like wide 220. Paper backing at both ends. As I recall, the thickness is approx. .004 inch, more or less the same as smaller roll film. Isn't sheet film about .007 in.? I love your Lee Friedlander quote. One thing with a Cirkut shot - everything and everybody in the area gets in the picture.
Charley - I've wondered myself about the eBay Cirkut buyers. I watch most all of it sell, and it seems there are a couple of the same names pretty often. Buying for resale? Compulsive hoarders? When I first looked at the link you posted, I thought Yikes, as far as the price for a basket case Attachment. But then I saw the gears included. That must have been what he was after.