Your local sandwich shop should do this for ya anyway, if you want one.
Mine does, at least! Had been for a while before Jimmy John's.
They hollow out a big kosher dill and stuff the sandwich fixing in there. It's a pretty fun novelty, but I think I prefer the bread they get from the bakery just up the road.
Support local businesses, Jimmy John's and Subway are but pale imitators and all that jazz.