It would be awesome but I doubt they'd be making DLC for such an old game, it would be hard to release it too even if they did, since a lot of the systems Bully was distributed on can't really update over the internet like modern games can.
Unofficial mods can still add a lot of great content though, so that's cool. SWEGTA and I are working on a pretty big mod at the moment called Bullshit that can sort of be seen as a DLC with all the new content it hopes to give players.