Ole, sounds like your quest to find proper plate holderes were a bit more succesful than mine.
Try locating Thornton Pickard bookcase style holders in 5x7, LOL. Sure, there's no shortage of quarter, half, and full plate sized holders, but nothing in 5x7. Oh, and don't get me started on full plate holders to fit Cycle Graphics - a gazillion different variations in holder styles out there, but none fits the camera in question properly (having spent 40USD for a single holder just to find out it won't fit can most certainly ruin one's day).