According to Mundorare, Banjo was shown to "selected press" last week. From the site:
It seems that only some selected media were allowed to attend this call; and as it’s obvious no information has seen the light of day yet, so without a doubt there are some NDA to avoid leaks until Rare approves the moment. This information has been extra-officially confirmed in the latest days through several boards (NeoGAF, RWP…) and even a podcast from 1Up, with Banjo-Kazooie 3 being one of those alleged projects. Apparently, those journalists would have played the game.
We're not saying this is true, but it completely is. Call it a wild hunch. Expect more very soon.