If the arthritis necessitates something with wheels, f/64 makes some nice lightweight suitcase-style hard cases with wheels and a handle built in. B&H often has them in the used section--not actually used but overstock or demo models. They also make some nice backpacks suited to LF.
For my 8x10" Gowland, which is ultralight and packs thin, I use an ordinary knapsack designed for laptop computers.
For my folding 4x5", right now I'm using a padded shoulder bag that seems designed to carry a laptop and a printer. I've been looking, though, at a Domke F-802E reporter's satchel, which looks nicely laid out for my setup, with two wide pockets on the outside that should hold two Grafmatics each. When I last checked at B&H it was out of stock, but I'll check back.