But I think I handled the chicken-and-egg problem in a pretty simple way - my selector/filter simply looks for the presence of the given service type in a bag, to determine if it should look up a selector/filter from the container. The bag is built by hooking into the ComponentRegistered event on the kernel.
When I implemented handler filters, I also got the impression that modifying this part of the container would be kind of tedious - therefore, I'm now proposing a solution that builds upon the existing behavior, without modifying a single line in the container.
My initial thought was to make this available as a facility (which is what I have done now), but if it proved useful then we could perhaps consider adding the behavior provided by the facility to the container per default.