Dear Joe,

They certainly made them in both 6.5x9cm and 13x18cm because I have several of both (as well as 4x5 inch). It would be logical if there were also 5x7 inch and half-plate versions with the same external dimensions as 13x18cm, though I don't recall any quarter-plate Linhofs.

Because of the spring loaded pressure plate they can be used with both film and plates, and indeed, I believe they wer aold (until about the 1970s) as 'film/plate holders'. The ejector arm also tells you if they are loaded, of course.

They are, however, damnably heavy and if you're buying, check the hinge on the bottom flap. They sometimes break there are are sometimes superglued back together.