Given that we are able to come to agreement about certain moral matters and the existence of moral progress, I do think that the evidence favor the existence of a well-behaved idealized reasoning system that we are approximating when we do moral reasoning.

What "certain moral matters" do you have in mind? As for existence of moral progress, see Konkvistador's draft post Against moral progress.

This for a start.

I've always found that post problematic, and finally wrote down why. Any other examples?