Rare games have a lot of easter eggs referencing their games. Diddy Kong Racing was the first and only Rare game to feature logos of Rare and Nintendo almost everywhere you go, but later in the game, one of the first Rareware cameos is also featured as a logo. It is hidden in Star City, part of the game’s last courses. If you drive/fly by too fast, you will miss it.
To my knowledge, the logo is removed in the DS version along with all the Nintendo 64 logos.