So that's how they're called... even though you can describe a lot of things being sandwiched (and not necessarely food), I can only imagine a "sandwich" as something triangular. That's why borgaurs are superior, you simply know what you're getting. And "submarine sandwich" is not consistent enough to match a "bocata".
Okay - so that triangle cut is along the lines of what would be called a 'finger sandwich' or 'tea sandwich' by most English speakers. Looks like the 'bocata' would more or less cover most long-roll (hoagie) sandwiches, based on the
Wikipedia entry. However, the 'usually served cold' descriptor in that does seem like it would tend to exclude things like meatball sandwiches and Cubans, as well as a number of hot deli meat subs. [Edit - misread the line as 'usually served cold with beer,...' rather than 'usually served with cold beer,...' - my bad.]
Anyway, here's a double with fries and (presumably) a chocolate shake from B-Bops. It eats better than it looks.