With hundreds of people working on a title these days and posting their resumes online it's hard to keep the cat in the bag when it comes to major new games. Freelancing concept artist and animator James Mosingols had put "user interface concepts for Borderlands 2" on his resume and was promptly asked to remove it. But it was too late.
It's not secret that Gearbox Software would love to do a sequel to the 2009 hit and as they wrap up work on Duke Nukem Forever this may very well be their next project. We might hear more at E3, but at this point it's just evidence that Gearbox has been prototyping Borderlands 2.