I agree with Rosie and Over&Out. That kind of behavior is disrespectful but attacking it head on can get you the cold shoulder from not just the teacher you reported, but from many others as well. It will most definitely won't win you any friends. Even those teachers who think the teacher should be dealt with won't give you any points for reporting him/her. Total double standard. You know how the police have their Blue Wall of Silence? Well, I don't know what color it is, but teachers have one too!
What I have done, and seen other teachers do, is to find a way to step in. If I'm able to, I'll often stop in the classroom if I hear trouble and try to distract with a question or something like that. If it's a kid I work with or who's on my eval list I will sometimes go back to my room and call the teacher on the intercom, asking if I could see so and so for a minute. Then, when they come to my room I give them a pep talk or a dumb errand to run. I know the other teachers try to do this too. If I'm co-teaching or pusing-in, I usually try to shield the student by pulling them into our group with a "Let me help you deal with this problem" kind of attitude. Also, in our school districts teachers often send students and their work to another classroom for a break (for the teachers AND the student :). Somedays you get the "problem" student, somedays you send 'em :)
As far as teacher-on-teacher bullying (which DOES happen....more often then some people would like to think), then it's a different ball of wax. But, at least in that situation, the person being bullied is an adult, not a child.
I really think it's a shame that they don't provide teachers with Early Burn-Out Identification and Treatment or something like that. Some kind of counseling to help teachers (and support staff....we are not perfect:) to deal with what has been (and is becoming even more so) an extremely stressful job. If the gov't pays for it for catastrophe workers, why not the people who are working with your child everyday? :)
Talk about dreaming Utopia, huh? LOL....