Thank you for the thoughtful reply.
We wanted the ReportNG tests because we were recently using them when our build was a Maven build. When we migrated from Maven to Gradle 1.3, we had problems getting the ReportNG listeners to work, so we backed off and ran with the Gradle default TestNG reports. Those default reports were not so attractive in Gradle 1.3.
I think we will be sufficiently happy with the Gradle 1.4 TestNG reports, however. I was just bothered by the fact I could not get the ReportNG stuff to work, hence my last-resort question above. I’m glad you had trouble, too 
Mark