There is a vietnamese sandwich shop on East 2nd Street, at the corner of Avenue A. They are delicious and they offer several varieties. That said, you can access it pretty easily by taking the F train to the 2nd Ave. stop. It's only a 2-3 block walk from there.
Agreed. It is a pretty good banh mi. I think its around $6 which is more than it costs in Chinatown but then again, most things are cheaper down there but if you can't make it down there, this is a decent substitute.
the furthest uptown banh mi option i know of is bao noodles. never had it so i can't comment. saigon banh mi is my single favorite food item in all of nyc, and its strange discordant location in the back of a jade jewerly shop alone is worth a visit.