Chop suey was once the rage for diners across the land but has long fallen out of favor.  A sandwich 'variant,'  however, that was found in parts of New England still seems to be a regional favorite, along with its cousin, the chow mein sandwich.


 
According to Wikipedia,
"Originating in Fall River, Massachusetts, in the 1930s or 1940s, the chow mein sandwich, which typically consists of a hamburger-style bun with a brown gravy-based chow mein mixture placed between and served hot, is popular on Chinese-American restaurant menus throughout southeastern Massachusetts and parts of neighboring Rhode Island. 
Typically, customers ask for their sandwiches to be “strained” or “unstrained.” This refers to whether they would like their sandwich with vegetables. If the chow mein is strained it has no vegetables.  

Anthropologist Imogene Lim published a good history of the chow mein/chop suey sandwich, including suggestions for how you can prepare your own versions of these sandwiches!  For more info, check this bibliography of newspaper articles on chow mein and chop suey in the sandwich format.