Boston doesn't have a ton but there are a few examples of buildings with small floor plates in that height range. They can be profitable but often there lots available for development are larger than that and it take either relatively short buildings or very high costs to make up for the loss in rentable square footage.
The smallest about 2,000 sf
Beacon Hill
4,000 sf
Harvard Square area
Three towers near the Harvard campus all 4,000 sf or less rotate the camera
Peabody Terrace
This is technically about the limit but it is only 5,000 sf so I am including this building in the theatre district as well:
Moxy Hotel, Theatre District