Printfile still catalogs them.
120-1M Continuous negative sleeve for 120 film. 1,000 ft. roll of continuous polyethylene sleeve, non-perforated. Cut the sleeve at your preferred size.
I've not checked to see if B&H or any of the other retailers still stock them, but they are listed.
There's also roll of them on Ebay now, but it's a little more expensive than buying two boxes of them directly from Printfile.
BTW, I've recently started shooting 70mm, and have yet to buy files/pages for them(the film I've shot is currently rolled up in the tubes my lab returns 120 in...). I was going to order some of the 120-3HB sleeves, but hadn't pulled the trigger because my Nikon scanner doesn't really handle strips longer than 3 frames of 6x6. The 70-3HB would be perfect, but it would also take a LOT of pages for one roll of 70mm.
The solution I'm toying with now is ordering some of the 120-1m sleeving along with some 8x10 pages(especially as I have an 8x10 camera I'm restoring and hope to shoot soon). Ideally, even if it's a bit sloppy, I could cut my 70mms as I see fit, sleeve them, and fit most if not all of a roll down in a single 8x10 page...