Driving through Billings a week ago I stopped at CAMERAS, 101 N 24th, (1-800-664-1776) and picked up some 8x10 hard rubber developing tanks. He had a number of 8x10 tanks, both rubber and metal. No 8x10 hangars at the time but he gets stuff fairly often. A ton of other LF film hangers including some odd sizes one doesn't see too often. Enlargers in the basement and a few LF view cameras on the main floor. Books and supplies and a ton of used film gear of all sizes.
If you are going through, heading to Yellowstone or Glacier or workshops at Formulary... the place is worth the stop. I don't work for him, just stop there every few years when I go through and always find something interesting to buy. Old brass lenses on the shelf and a ton of 5x7 and 4x5 film holders and most of the stuff I asked about was priced reasonably.