I love Banh Mi! I used to have them a lot when I was in San Francisco. A French roll stuffed with meat and veggies for $2-3 - it was unbeatable!
While we're talking about sandwiches, has anyone ever seen the WQED/PBS documentary "Sandwiches You Will Like"? It's an incredible program all about different specialty sandwiches all over the US, including a lot that have been featured in this thread. A word of warning, though - you will want to do a road trip after watching the program. And unless you live in the middle of the country like Punisher Bass or Dogbert, that's just not feasible.
I'm sure there are some torrents out there, but I'd recommend buying the DVD if at all possible - it's definitely worth it, and you'd be supporting Public Television.