Went recently to Alive and Kicking Lobsters in Cambridge to try their version of a lobster roll -- except that they call it a lobster sandwich. Here's a report:
Bread: they don't use rolls -- instead, they toast and butter two slices of scalia bread before scooping on the filling. It's an effective if unorthodox choice, the bread being of good quality and the butter imparting an extra splash of richness. There's no lettuce or other distractions.
Filling: this is really more the lobster salad type of entity, with a modest amount of mayo, smaller chunks and shreds of lobster meat, and no celery or other items. There's a nice sweetness to the filling, perhaps indicating fresh-picked meat. No large hunks, though.
They include a small bag of Ruffles potato chips with the order. Price is $12.95, a good deal for this kind of item.
Ambiance: this is primarily a no-frills store selling fresh seafood, with little else on the menu besides the lobster sandwich, though they do bottle their own sodas (didn't try one). Surprisingly, there is a small picnic tabled eating area outside that evokes the feel of a clam shack, with a covered area draped in fishing nets festooned with plastic sea creatures.
I enjoyed it, though it may perhaps not be everyone's idea of the perfect lobster roll.