MS Gamer's Day: Banjo hands-on
As far as we know this Kotaku piece is the first actual playtest of Banjo Kazooie: Nuts & Bolts beyond the pre-embargo previews. Sounds as though Brian had a nice time making vehicles. There's a very telling quote included there, right at the end: "Creating vehicles to complete the challenges is the crux of the game."
Have a look.