Julien,
I would be happy to offer my services for this assignment, recently I've done a lot of work with Java3D and I'm hoping to continue to work with it, though the vagaries of emplyment may or may not allow me to.
The benefit I can bring if you decide to give it to me would be an intimate knowledge of Java3D (on windows and android ) and a host of minor bugs and their work arounds along with a stack of performance enhancements.
Until recently I knew very little of the pipeline, jogl and opengl, however I now have a working knowledge of all 3.
The downside of me being the maintainer would be I know nothing of jogamp coding and release standards, I also haven't work much in a distributed team so on both those fronts I expect I would need a lot of hand holding through the early code changes and releases to make sure I did it correctly.
I also don't have access to a Linux or MacOS machine so bug reproduction and release testing might be cumbersome.
As I understand it however you are not expecting to do more than a few maintence releases per year with no breaking API changes.