Zip ties used to be sold in a plastic container about 3-4" wide and about a foot high. You can also still find old Saltine cracker tins in antique shops that would work. And around Christmas, EVERYTHING seems to come in a tin, and that's a good time to look for them.
Both oatmeal and cornmeal come in a smaller, bagel-sized waxed cardboard container, as do raisins.
A large cottage cheese, ricotta cheese, or sour cream container might work as well.
I prefer bagels for tripping because of their shelf life and durability. I find the raisin ones last longest; something about the moisture in the raisins seems to keep them soft and fresh-ish... Regular ones get too dry for me in a week, and english muffins seem to crumble by day 3. Tortilla wraps work well, but I don't really like the taste. Some of my friends swear by them though. Naan is pretty durable too, and I like it well enough.
And I'm not sure if they sell it commercially, but the Army used to issue us "shelf-stable bread" in a brown foil wrapper, like an MRE... it was like two heels stuck together, with the crust on all 6 sides, but still 'bread', and if you were hungry, you ate it and were happy. (There was shelf-stable milk too. Vanilla was 'eh', and chocolate was very good.)