arguments of Java3D vs Xith3D aside (my personal preference is Xith3D but that is what best suites my needs - just pick whichever is best suited for you).
Creating a Java3D binding of Odejava is very easy, especially since the addition of the org.odejava.display package which abstracted away most of the binding stuff.
Here's some text I wrote to another person about this exact topic (even about Java3D so maybe he might have gone and made it - even if he did it's not much work anyway):
All you need to do is implement org/odejava/display/DisplayTransformable.java using your display library. You can use the Xith3D object Xith3DDisplayObject as a guide.
Optionally you can create a utility for Java3D similar to
OdejavaToXith3D which can automatically create Xith3D objects based on
the ODE geom.
That's it! Not rocket science eh? All you have to do is port Xith3DDisplayObject to Java3D and vola - you've got your binding. The interface you need to implement consists of only a few methods. It's even easier for Java3D because TransformGroup is fairly similar between them.
Harder to port is the OdejavaToXith3D class - but that is optional. If you are porting it, please talk to me first as there is some deprecated code in it which you don't want to port.
The official documentation is here: http://odejava.org/javadoc/org/odejava/display/package-summary.html#package_description
The interface you need to implement is here:http://odejava.org/javadoc/org/odejava/display/DisplayTransformable.html
(1 method! how easy can we make it?)
If you have any queries - ask away
Please feel free to share you code once complete (better to submit an enhancement issue or email it, these forums kill indents).