I know nothing about the backpack or the size of it, but a 4x5 norma can be made somewht portable. I could definitely give some measurements in different ways of folding. IME experience there are really two ways to compact one. First is the one in the Norma docs which is to move the standards to opposite ends of the 12 base rail, disconnect the bellows from one of the standards, then use the tilt adjustments to fold both standardstowards each other.
The other approach is to keep the bellows in place, make sure the frames are dropped as low as they go (fall), then push both staandards together. This can possible made more flexible by sliding the standards off the 12 base rail, and onto a 6 inch externsion rail. This may require removing the rail clamp from between the standards. I used the offcial approach, the it doesn't come close to the compactness (or weight) that you'll get from a folding wooden field camera like a Chamonix, Shen Hao, etc.