In fact, this is not entirely novel. Pit Hartling has published this idea twice: once as "Sp!it Second" in the August 2000 issue of Genii and again in Card Fictions under the title "High Noon". Neither uses the Mercury Card Fold as Dustin implied in his review of McCullagh's trick -- they both use duplicates cards and a force. Still, the idea is not new. Pit Hartling credits Marc Sicher and Steve Cohen with the inspiration for reproducing the card under the watch in the Genii description. In Card Fictions, he states that he developed the combination of Paul Harris' "Reflex" (aka "Whack Your Pack") and Card under the Watch with Andreas Buchty from Freiburg and that Marc Kanert of Frankfurt "also experimented along the same lines.""Card Watch" is a novel ending for Paul Harris' "Whack the Pack" (credited) where the thought of card appears folded under the spectator's watch.
Also, while I don't have the materials to fully give credit here, I believe that Carl Andrews' "Deja Vu" is a predecessor to McCullagh's "Sweet Dreams of You". It uses a dream presentation (and a triumph effect) and ends with an odd backed card being revealed as the signed selection (ala Sankey's "Paperclipped").