As Cyrax151 has made us to notice and as we can see in the Youtube Channel of Gutmanship, if you pop the Twisted Metal Black PAL disc in your PC and try to check the “MOV” folder, you can find some small video-files (less than 1 second) that when converted to .wmv format show a series of unused character intros. These are similar to the ones that are used for the playable characters in the game, but we can even find one for Warhawk, the final boss that is not usable by the player: is it possible that Warhack was meant to be playable originally?
Videos: