Judging from the somber reaction it produced from both Naruto and Jiraiya, I can't imagine it would be something as 'tame' or inspiring as the teleportation technique. I'm more inclined to believe that it is the Tailed Beast Bomb, but even then, I have my reservations. Referring back to the tone that Naruto and Jiraiya had when discussing the technique, one would assume that they attempted it on some level and may have failed. However, when Naruto first tried to form the bomb in front of Bee, it seemed as though it was his first time seeing it.
It's fair to say that maybe it was his first time reaching such a level or that even if he had hit upon it before, it was in the mindless kyuubi cloak state, but I think he would've at least recognized the 'feel' of the chakre he was molding.
I'll be honest and say that I'm banking on it being a whole new technique, but at this point, that's highly unlikely.