There is a roll film holder on Ebay at the moment, item number 1289746373, I have never seen anything like this before. Does anyone know anything about it? Was it a standard production item, was it made by Graflex? Was it a one-off device for some special purpose? What film did it use. What was it for, use Speed Graphic as a mini aircraft camera or something?

I'm not bidding for it, I'm jst interested.

HUMMMMM very interesitng!!!
My best guess is it is a limited production (not Graflex)back for school pictures. Probably went on the back of a RB Graflex with the older style back. With a 50' roll of film you would get about 120 pictures.
The way the 4" side is masked down looks like maybe about 3" wide roll film ( 70mm?) not sure. Email the seller for the film spool size and the exposure area.

Doesn't look like a military item for aerial photography, too wimpy on the winding mechanism, and the add on film counter look a bit make-shift.

Thanks for the brain teaser
hope this helps