don't know when the "full" bsp tree support can be "added"!! it should not be so hard to add that we have waited for so long
btw,
the current triangle selector does too much work that a duplicate octree was created to exploit the octree scene management, is that needed? I suppose not, why don't we use the original octree saved in the node to do the culling acceleration?
You could always try adding it yourself. Niko has a HELL of a lot of things to work on all at once to please anyone. Also, he seems pretty busy with his studying so either wait patiently or attempt to do it yourself. As you say, it shouldn't be difficult