The latest edition of Conrad Waters "World Naval Review" has a detailed rundown on the Japanese DD-115 Akizuki destroyers - a non stealthy general purpose design - what caught my eye was (first of class):-
Started July 2009
Launched Oct 2010
Commisioned March 2012
less than 3 years - the T45's are 6 to 7 years in construction...............
The book also reviews the Zumwalt - that 16,000 ton "destroyer" which also has taken 7+ years to service