Seems like a good morning for a monkey riding on the back of a Rhino. Game archivist Andrew Borman of PtoPOnline shares video and background information on Climax Studios' undeveloped pitched for a sequel to Rare's Diddy Kong Racing.
Diddy Kong Racing Adventures is the name of the game, and had it been picked up it looks like it would have been a pretty cool combination racing and adventure game for the Game Cube. The vile Wizpig and the Kremlings have plans to pave Diddy's island paradise and put up a raceway. Diddy must travel between various race locations via a massive hub world in order to liberate his island nation from oppression.
Though pitched with the Game Cube in mind, Climax developed what we see here on an Xbox, as that's what they had to work with. The Diddy Kong Racing Adventures pitch was created in 2004, the same year Climax released action RPG Sudeki for the original Xbox.
Obviously Diddy Kong Racing Adventure never came to fruition, just like Rare's own proposed sequel, Donkey Kong Racing, which fell apart after Microsoft purchased the developer in 2002. The last we heard from the franchise was the 2007 Diddy Kong Racing remake for the Nintendo DS.