Not wholly proud of this booking (actually on hold), but here it is:
4 pax
CUN-BOS
AA in Y
37,500 AA + $51.94.
It's for Sunday at the end of a holiday week, so I felt pretty good about just finding anything available, though it's painful to see the Saver award (15,000 AA) available on the next day.
Of interest (at least to me), I was able to reserve seats in Main Cabin Extra, even though I don't have any status. I do have the AA Citi Exec MC, but I don't think that's what gives this seating, does it?)