I've got a fancy-pants consultant longtime friend who does a lot of expert witness work who now swears by these online guys:
Black Lapel
Whole process takes less than a month.
I've not worn a suit for years, but may have to for an upcoming project, and am strongly thinking about giving these guys a kick at the cat for a couple of custom suits and shirts. Khakis with a Guayabera or Aloha shirt have some social limitations.
What is the price range for a custom summer weight light wool suit in the DR? I have seen some really bad suits and jackets here.