Has a World Baseball Classic game ever ended 11-6?
It has. 11-6 has been a World Baseball Classic final 2 times in 204 games. The first was Venezuela beat Spain on March 10, 2013; the latest was Japan beat Cuba on March 7, 2017.
That makes 11-6 the 27th most common final score out of 80 that have ever occurred in World Baseball Classic. One point away, 12-6 has happened never and 11-7 has happened 1 times.