Ok, I hope this does not violate forum rules being this is regarding a scanner.
I know this is a long shot, but I have a Sprintscan 45i that appears to never been used, but missing the film carriers. Looking to see if someone has any of these or a parts machine they might be willing to sell. I believe the holders from the prior version, 45 and maybe the 45 ultra would work. I need the 4x5 carrier and I believe the inserts for 6x7 and 6x6.
I have one from a Sprintscan 45 (I have the scanner too but they are big so shipping would be expensive.)
It has the 6x7 insert. The 4x5 holder is very well made.
The 6x7 insert is kinda silly. They actually use magnet strips to hold it down.
I made my own magnetic strip and it works much better than the originals.
Great scanners. I moved to an Epson 700 just recently.
Anyway, the holder and insert for $50.