One of more interesting exclusives that Nintendo had during the Wii era was a title called Epic Mickey. It was a tale of a more classic Mickey Mouse delving into a world of forgotten toons that was on the verge of being erased. The game was well received, and did well enough to get both a sequel and a spinoff for the 3DS called Castle of Illusion. It itself an homage to previous Mickey games. Now, it’s come to light that another title in the Epic Mickey line was planned. This time though, it was a racing game.
As found on the Epic Mickey Wikia, Epic Disney Racers was a planned racing spinoff for the gaming series, with concept art made to show off its potential. It would have included many of the Epic Disney characters, including Mickey, Oswald and the Mad Doctor, along with classic Disney characters like Scrooge McDuck and Cruella De Vil.
Interestingly enough, the game was set to presumably follow a Mario Kart Double Dash approach, with each car having two drivers. One to steer, and the other to possibly attack other racers. The project was cancelled early on in development, possibly because of the low sales of Epic Mickey 2 and Castle of Illusion. It’s unknown whether any other games were meant to be made, or if the series will ever be back.
Source: Epic Mickey Wikipedia