Recently tried the much-vaunted lobster roll at the Raw Bar in Mashpee. For some folks, this will come very close to their ideal version.
For starters, it's huge -- have never seen so much filling in a lobster roll, pretty much impossible to pick up and eat. And the filling is fine stuff indeed, cleanly flavorful with no celery and only a moderate amount of mayo coating plenty of smaller shreds and a lot of large claw chunks. There's also no lettuce used on the sandwich.
Roll: a generous sized top-split hot dog bun is used. It's not grilled, and from what I could see, there may not be a spot to do so on the premises.
It is definitely not cheap at $25 and change with tax added. It is not served with any sides.
The place itself is small, a moderate sized bar with a few tables inside and an outside seating area. Given the relatively fancy and touristy shops and eateries surrounding it, it's a refreshingly neighborhood-like anomaly. Service is capable if not exactly warm and fuzzy. It's a little hard to find, but I thought well worth seeking out.