Doing some optimization of the OpenGLContext scenegraph.  Just using display-lists on the material objects takes the material rendering overhead from ~5% of runtime to <1% of runtime.  There's a diminishing set of low-hanging optimizations available at this point.  The wrapper object is obviously a major time-sink.  I took a look at re-writing that in C and then realized that mucking about in C just isn't something I want to do.  Yes, it's a trivial little extension object, but I don't want to spend my "relaxation" time on programming C.  I get enough of that at client sites.

I think I can save around 8% more if I cache the typed children-sets for the traversal code.  There's millions of isinstance calls due to the generic form of the traversal code.  Just providing a cached set of traversal-types would be a huge win.  Would probably also be worth it to cache the paths to special nodes (lights, backgrounds etceteras) with invalidation on "children".