Barack Obama wins the endorsement of the United Food and Commercial Workers. They're one of the youngest unions around in terms of membership, and have a substantial presence in Ohio. There's an interesting subtext in this race whereby Change to Win unions have tended to be sympathetic to Obama, while Clinton's key pillar of support has been the public sector unions. This hasn't really spilled over into any incredibly concrete policy controversy on the campaign trail, but probably has some implications as to how they would govern in that you naturally take the concerns of the unions who supported you a bit more seriously than those of the unions who tried to beat you.
UPDATE: I had initially intended to make a joke about "impressionable elites" showing up at the most unlikely places, working in supermarkets and slaughterhouses and such but I'd forgotten that unions with four-letter acronyms don't count. AFT! NEA! AFSCME! Those are unions. HERE, UFCW, SEIU and so forth don't make the cut.