You heard of the guy from SpazioGames who spoke about Zelda Wii (giving out 10 general details about the game)? In the SG forum we could ask him something about the Wii (everything but he could decide to not respond if he hadn't the permission)...one of the question (the first question to be onest) in the thread was about Pikmin 3, and he responded that Pikmin 3 is not in the work, and is just an idea for the future...he also added that the words of Miyamoto at E3 2008 had been misunderstated, because he never said Pikmin 3 was in work.
This guy works for NoE, so there's also the possibility he's lieing to keep the secret, but I think this has a sense at all...