40 Winks (found Nintendo 64 port of 3D platformer; 1999-2000)
40 Winks was a platformer game developed by EuroCom, for the PlayStation. However, a Nintendo 64 version was planned, and was indeed at the very end of development, even receiving a review from the Official Nintendo Magazine. In late 1999, the publishers debated whether they should, in fact, release the game for the Nintendo 64, with IGN calling its future "uncertain". The carts were ready to be shipped, and yet, it was never released.
The English, Spanish and Italian prototypes were released on a popular ROM-hosting website, and it can be discovered through a simple Google search. It is currently unknown why the game was cancelled.