During his own stop at the Liberty Hotel with last year’s “Source Code,” rising genre director Duncan Jones, admitting to a bit of “Dredd” envy, shared an unrealized pitch for tackling the material from precisely this perspective. “I thought it would be great to approach it as a documentary following another guy through this incredibly interesting, crazy world,” Jones said, “with Judge Dredd as a character whose influence has terrified the city, but who’s only seen in cameos.” Laughing, he added, “Obviously that’s not an easy sell: I’m going to make the Judge Dredd movie, but he’s hardly going to be in it.”