Here's a couple of 9x12 fit Rollex roll film holders, nominally 6x9, both give a frame size of 56mm x85mm with slightly rounded corners.
The left hand Rollex fits the Rodenstock & Orionwerks cameras, the edge details shown here are similar to the plate holders.
The right hand Rollex fits an early 9x12 Linhof.
Width of holders: 99mm (100mm Linhof fit) Length 150mm
Any other information would be greatly appreciated.