I've been searching for the designer's quote, but can't find it on the boards. One of the staff members (would like to say James Jacobs, but not sure) stated prior to UC's release that there will be a feat (or some sort of ability) for the gunslinger to reload while wielding two firearms.
So far, the only thing I see is the Ghostly Reload SPELL...and nothing else. And Gunslingers are not spellcasters so that seems a bit preposterous to have unless you plan on multiclassing.
If I find the quote, I will post it here. But sadly, I don't know any official ruling on this and am also saddened we were not given something semi-promised. :(