My good friend has a little girl very much like your son. Love and Logic has worked very well for them, with the key being 100% consistency in cause and effect. Ie: you kick, this will always be your punishment, even if it is at the fair or at the mall. You punch, this will always be your punishment, even if we are at the fair or at a restaurant.
They attended a Love and Logic class at a local church and said that it helped them far more than reading the book because they could bounce ideas off of the other parents.
Just a thought.
I'm so sorry. It's SO hard when we see our children behaving badly when we know their true spirit is sweet and kind. It hurts our Mama hearts.
"Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment." (Matthew 22:37-38)