9x12 holders with film sheaths do come up, I was frustrated for a while, but then found 12 very good Kodak ones. I love my 9x12 camera, 4 different lenses + Rada roll film back
and masks for 6x4.5, 6x6 and 6x9, it's a really wonderful system. Sometimes I miss the squarer 4x5 format, but 9x12 is very elegant. I like the ground glass and find that I take more time
for fotos and am happier with the results.
I got three from one of those buy-it-now sellers on eBay for $20! Just shot them yesterday first time with some hand cut HP5. Developed last night, got a little light leak going on, but I gotta say those Kodak holders are pretty well engineered but cumbersome in the darkroom. I need to bend one of mine back to normal. Then I'm going to sand down the gritty roughness of the dark slides and clean out the rust on the springs and anywhere I can find it, and then I'm going to repaint the items that were painted black, and dry lube the channel the dark slide goes down so the dark slide will be super slippery once it is pulled past the end clasp.
I love the wilderness and I love my trail cameras, all Fuji's! :) GA645, GW690 III, and the X100 which I think is the best trail camera ever invented (to date).