If you are not going to use a changing bag, then I agree some kind of film holders could be useful. You might consider your likely use of the camera too... a simple box is easy to make or find, and you might be able to make several in the time it takes to make one that will accommodate a film holder.
A "single shot" camera isn't awful, and it has some positive side effects. I often take my coffee can camera out with a single piece of paper in it knowing that I can only make one picture. There is a certain mindset that happens when you know you only have one exposure to make, and I enjoy it and like the "finality" of it and wondering how it will come out as I drive home. I have some old cameras that I use this way too and it makes the selection and taking of the photograph special... it focuses your attention! The changing bag and extra paper come along when it will be a longer photo day.
With 8x10 negatives, since I will be planning to contact print them, I can imagine mostly working this way even if I have the ability to change paper in the field. Making two or three simple cameras instead of a more complicated one for film holders or changeable paper is something I'll consider.