Kinematic management (integration, interactions)

[MaxDZ8]

I'm asking for some sort of brainstorming here. Please dump everything you might think useful as I'm running out of ideas.

There's often the need to make a kinematic object work as a dynamic one. I initially considered about a tracking/synchronize method but dropped it. I have then pulled out my old integrator to be applied to kinematic bodies. They don't quite look like bullet's dynamic but they are acceptable.
Problem is the performance is much lower than expected - debug builds are unusable (making debugging painful) while release mode is barely ok (too little room for the future). My best bet is that my integrator is forcing bullet in computing much more than it should. I'm going to look at it in detail this afternoon.
In the meanwhile, I'd like to hear your experiences in providing physical simulation to kinematic objects.

I was thinking about providing a budget and interleave updates but I don't expect to have much of a gain given the low amount of kinematic bodies to simulate (I'm only at 15 right now)!