NBC chief digital officer George Kliavkoff has raised the prospect of an NBC return to the iTunes Store, claiming that the network would “love” to be back, though price and piracy concerns remain sticking points. Speaking in an on-stage interview at the Ad:Tech conference, Kliavkoff said, “If you look at studies about MP3 players, especially leading MP3 players and what portion of that content is pirated, and think about how that…