Have you tried Military uniform shops? You may need to get a service member to check for you but you description sounds a lot like:
a. Officer/ Senior Enlisted Navy/ Coast Guard Dress Blue. We call it blue but it is black except in the most extreme light.
b. Army Class B [the green dress/ office uniform] which may have a blue/ black equivalent.
c. if the US services have something that close it is a good possibility that Can/ UK/ Aus/ NZ might have exactly what you need.

good luck