The Just Cause team ran a contest recently wherein fans of the series could create a trailer, and a winner would be selected as the game's launch trailer. Since the game launches tomorrow (December 1st) it's about time for that trailer, and here it is.
If the comments and likes/dislikes on YouTube are to be trusted, it seems the trailer has received a bit of a mixed reception from the community. I think it's pretty funny; the whole idea of a fan-made trailer suits the mood of the Just Cause series perfectly. And as the team says in the description, "We think this trailer is fun and different...and doesn't take itself too seriously...just cause. :)"