Other than niche market requirements for nose loaders (such as Atlas), industry trend seems to be moving the other way . . Pax carriers, FedEx, Luffty (Lufthansa Cargo), and others don't agree . . . not even a super big 747f (the scarebus 380f) had found significant demand.
I applaud the 747-8, but also expect that they will prove to be the last of the "two engine on one wing" aviation era. . . . . for profitable quirky economic long haul, expect for the 777f to eventually kick pants.
As for a soon to be freight market recovery. . . . . Other than the progressing population bomb, and with nothing to reverse today's job loss, what magic potion out there will break such a spell?