Racer_S (who runs http://www.tocaedit.com/) is probably the most prolific widescreen and Surround hacker on the Internet. He is responsible for more high profile FOV and Camera hacks that anyone else. This page lists most of the hacks he has produced, including some not directly related to widescreen gaming (e.g trainers, controller emulators). Hacks for individual games have been attached to the individual DR pages on the site.
Racer_S wrote a hack for Just Cause with the disclaimer - "May work for other games." Guess what? It does. Copies of the URes Changer have been attached to the DR pages on the site. Feel free to grab a copy and try with other games as well.