Going back slightly further, I'll offer up some evidence I recently stumbled upon.
http://imgur.com/a/FRpcx

This is the 1803 crew list of the Brig Washington which departed Salem, MA enroute to Isle de France (and presumably the East Indies Trade). While I was initially looking for black crew members, What held me up on this one was the 8th entry, which lists a French 15yr old seaman as 4' 1.5".

Unfortunately, this document offers up more questions then it answers. How did he come to be in Salem? Did he ever come back? Die here? Is his name misspelled, or was it a cruel name imposed by someone? What does it say that he was hired as a sailor ahead of the other men listed?

In any case, that he is listed halfway down the list, and his being a seaman speaks to his ability by that point and what could have been a longer career.

I asked about the topic with a local scholar on the East Indies Trade for his knowledge - and he recalls the son of one of the Boston Brahmins (want to say Cabots, but not sure) being born a dwarf and unlike his brothers who are receiving formal educations he ends up working his way up as a mariner and peaking as First Mate.

So I can offer that they are being involved in industry (1803 is still within the peak of Salem as a seaport), and have at least some mobility depending on opportunity, skill, and other connections.

Source: NARA-Boston, ARC 1600758, 1600870, 1600759.