The CIA's former Chief of Disguise says they very much exist and are used, with some limitations [1]. Her comment on the 3d printer making the mask: "What if I said we had it".
Of course that's not really surprising when you look at the kind of Halloween masks you can get if you are willing to pay [2]. I imagine if you could special order them to perfectly fit your head they would be very convincing to the casual observer and to software.
I'd like to see Mission: Impossible type transplants, or even masks like the ones they use, for that matter.