Ok, now at least I got it "partially" working. The issue seems to be using "-Dsun.java2d.opengl=true". When explicitly enabling the Java2D OpenGL pipeline you lose correct vsync support for GLCanvas and GLJPanel. It seems that Java2D is interferring in some way with JOGL thereby destroying correct vsync support.
The pragmatic solution is not to use the OpenGL pipeline of Java2D in conjunction with JOGL. This is a viable way when only using GLCanvas but unfortunately when using the GLJPanel to conveniently intermix 2D/3D you completely lose hardware acceleration without "-Dsun.java2d.opengl=true".
So I have to choose between "horribly slow OpenGL rendering with convenient 2D/3D intermix and correct vsync" or "full hardware accelerated, vsynced OpenGL with pain in the ass Java2D intermix" ...
Anyone got a better alternative ?