Hi,
Just wanted to direct your attention to a new post (http://blog-dev.wholebraincatalog.org/?p=32) on the Whole Brain Catalog blog about rendering a large number of neuron trees in our system which runs on JME2. You can see this in action on our YouTube channel (http://www.youtube.com/watch?v=nKM90Uc0Qic).
The blog post points to our wiki page for this example (http://wiki.wholebraincatalog.org/wiki/DeveloperExample-Cloud), which explains how to get ahold of the source code that makes it possible.
Thanks,
Stephen