Hi Sal,
i tend to think my preference for carrying will really depend on the type and size of sharpening method or system, and that will depend on the grind of the knife, but for what it's worth here's my thoughts..
1) A pouch integral to the knife sheath would be good as long as it's secure and isn't clumsy. It begs the question of what size pouch, will it be somehow "universal" and if not, for which sharpening stone or which method?
I can see only really imagine an integral pouch working for me if the package also comes with an excellent method of sharpening, one that is best suited to the grind and that can be used to both restore and maintain the edge. Spyderco have an excellent reputation for their sharpening products so i'm sure that would be more than possible, if a knife came with a field sharpening system included, one ideally suited to the knife and grind, as long as it wasn't prohibitively expensive it could be ideal.
2) A seperate pouch would also be good, might be a good balance if it can be readily attached to the sheath or worn on the belt , round the neck on a cord, tucked in a pocket etc.
Might even be nice on a sheath or seperate pouch to include a flat surface, maybe even removeable/replaceable sacraficial strip of leather that could serve as a strop.
Seperate pouch would also mean if the user prefers another method of sharpening, they dont have to carry an extraneous piece of kit or empty pouch (as they would if it was integral).
I quite like the idea of a versatile, modular set-up that can be changed or expand, depending on preference and need, . It leaves room for kit to develop and change. It can also mean you don't have to shell out for everything at once if you can't afford all the bells and whisles. ( pouches aregood as long as i'm not going out looking too much like inspector gadget or Batman...well...maybe batman's ok...if his outfit comes in muted colours
)