I'm with swansont on this one. I attend public high school myself, and I can't think of anything you could do to students to make them start respecting their authorities. That's something you have to start when they're not even in school yet.
You can, however, make things a little better by adding in extra consequences when the school sends your kid home. Pick something he loves (the Internet, for example), and cut him off from it for a week. (Being grounded is nothing to a teenager. Virtual groundings may be worse.) Threaten to have the cell phone company turn off text messaging on his phone -- and follow through with it.
Of course, you may only succeed in making him hate you.