@Slash
May I point you to the comic book (one of the best comics I've ever read made in the US) and the video game (such a hot title that they re-released it for the PC in 1999, 5 years after it's original release for the Atari Jaguar) before you pass judgement. Also I should point out Predator 2, which showed an Alien head in the "trophy room" of the predator's spacecraft.
This project has been drempt of, off and on, since 1988 or so.