What is bigger than a NY Sandwich? Pretty much nothing. Think of a Second Avenue Deli corned beef sandwich that people under 150 pounds (me) usually need to remove 6 slices of meat from, in order to consume it. There's your proof.
There's a new book out called The Big New York Sandwich Book. It's got sandwich recipes from dang near everyone running a restaurant kitchen. It's even got a page on how to make a "slow" sandwich, penned by yours truly.
I leave you with this, a Socratic dialogue on sandwiches, from "Friends."