My suggestion:

The bullies cough and wipe the dust from the fallen wall from their eyes. Close-up of Adela Pennyfather's terrified expression. Cut to the final shot in the movie: An epic super-slow-motion shot of Jill, Eustace, and Caspian emerging from the cloud of dust towards the camera with weapons draw. "FORRRRR NARNIAAAAA!!!!!!!!" Fade to black. Roll credits.

The bullies cough and wipe the dust from the fallen wall from their eyes. Close-up of Adela Pennyfather's terrified expression. Cut to the final shot in the movie: An epic super-slow-motion shot of Jill, Eustace, and Caspian emerging from the cloud of dust towards the camera with weapons draw. "FORRRRR NARNIAAAAA!!!!!!!!" Fade to black. Roll credits.

That kinda makes it sound as if they're going to kill everyone.

^ Hehe yep.

The unrated directors cut can have an additional scene after.

Although that would contravene the movie-makers' law that when an evil character is killed, they never show it on screen, but when a good character is killed, they show it in every gory detail.

I can see that scene being cut out, though it will be a shame if it isn't done right. The ending of the Silver Chair was, for me, a very poignant moment (even mixed with that little bit of comedy). At least they shouldn't leave out Caspian spending even a couple minutes on our world––I love that he gets to live out that lifelong dream. The scene where he comes back to life always gets me all emotional. It's just one of the beautiful moments of the series, and they better do something with it in the movie. No more leaving out the best moments of the book! (I may or may not still be bitter about taking out Aslan tossing Trumpkin around in Prince Caspian).

As far as the right or wrong of the bullies' treatment... you know what they say: "Spare the rod, spoil the child." It seems to me that less than what they received would not have affected them quite as much (or caused the ruckus that necessitates the inquiry into the school), but then again, Aslan roaring at anyone could have any number of effects. I mean, come on, it's Aslan. Still, I would rather they keep some of the integrity of the scene. But then again, I'd rather they keep all of the scenes the way they're written, because that's how I love them :T

Is Silver Chair still happening? I'm not up to date with this info. =p

They'd probably change the scene to a forced duel between a bully and Eustace. Kinda like Eustace's forced duel with Reepicheep in Voyage. Then they the bullies try to cheat and that's when Caspian and Pole come in and school them.

...nah they'd probably just do the duel, Eustace wins and bullies run scared.