JB,
I believe that all behavior is just a form of communication - he's telling you something. I'd guess it's frustration. But the question is with what. My son was a lot like yours. Behaviors resolved with changes in his educational programming. But we still don't have that right and behaviors still crop up. And new ones emerge as we deal with new issues. For us the recent concern has been more in terms of his friends or, I should say, lack thereof. I think our son is acting out more lately due to his sense of not belonging.
I do also think that the behaviors you are seeing are more typical of a 6 year old who is gifted. My step daughter was just visiting with us (half sister to MrWiggly). She hadn't seen him in 18 months. She commented twice on how he seemed like "a little teenager" and noted his sarcasm, talking back and such as being much older than she expected him to act. I felt validated when she brought it up on her own as this is what my DH and I have felt about him for a long time! I think the "teenager in a 6-7 year old body" is a common phenomena in gifted boys!
