We had an incidint similar down here in San Antonio a few years ago. It wasnt a coach punching and ump, but there were some physical altercations. Here's the story(I wasnt there, but I was with the assignment director while he was on the phone dealing with this and he relayed it to me):
In the 3rd or 4th inning of a little league game, the H made a call at the plate that upset one of the coaches. He ran out onto the field waving his arms and screaming at the ump. Being a seasoned vet, the H held up his hand and very loudly told the coach to stop right where he was and go back to the dugout. The coach refused and continued running up to the H and screaming in his face about the call. The H told him that unless he toned it down and began discussing it in a civilized manner he would be ejected. Again, the coach refused to obey the H's command. Naturally, the next step was to toss the coach. This caused him to throw his hat on the ground, kick dirt, and start chest bumping the umpire. It took a number of parents and game administrators to physically remove the coach from the field.
About another full inning passed before an armed officer came onto the field to speak to the umpire. Apparently, the coach who was ejected was also a board member and had called the police to remove the umpire from the game. The H was in utter disbelief, but obeyed the officer and left the game to his U1 to call. Afterwards, he called our assignment director to explain what happened.
In the end, the director told the H to go tell the U1 who was now behind the plate to get off the field and leave the complex for the rest of the day. He also called all the other umpires who were working that tournament and told them to leave as well. He called the other members of the board and told them until that coach was banned we would never call their games again and that they would need to find replacements for the rest of that tournament. Great move, IMO