Yes, the 'private branch' looms over the current 0.9.5 public tree. Ready to pounce upon it's prey and take it's place as the new development branch. Will it happen before 2008? Stay tuned, kids. I've got pretty far with the new libfreyja 0.10 design, and I'm even working on the new C ABI for some of the new classes. Basically, the new design is very much grounded in by the book software engineering opposed to the crufty maintenance chaos in the 0.9.x branch.
What's changed? New Scenegraph, focus on parallelism, new rendering pipeline buffers, reduced interfaces to make writing plugins in C/C++ easier, and a general focus on using proper data structures everywhere. That's just the backend. I don't have any interface features to show for 0.10 yet, so just know I'm trying to make the magic happen before the end of the year. Expect the private branch to hit public svn with in the week.