That's the thing. Besides the safety issue (NOT a small consideration) when do these guys find time for this stuff?
Powerball is a game some youth coaches use to evaluate players early. There are variations of the game. However, I don't know of any version where the players are allowed to hit one another. Here's a version of it:
Use about a 40 x 50 field. Doesn't have to be exact.
Each end of the field has a trash can. Surround the trash cans with cones or tackle dummies to create a 'No Man's Land', Dead Zone or, whatever. Usually about 2 > 3yrds of space all around the can is sufficient. The idea is to make the teams have to toss the ball into the trash cans to score. No dunks.
5 > 6 players per team. Numbers can vary.
Coach throws the ball in the air. Whichever team gets the ball advances it towards the other team's goal. The team advances the ball by passing. No player with the ball is allowed to run more than 3 steps before passing the ball off to a teammate. Doesn't matter which direction the pass/toss goes.
The defenders are trying to touch the player with the ball. 2-hand at waist is the norm. The BC has to immediately stop and pass the ball if he's touched.
The ball changes possession if the BC takes too many steps. The pass is incomplete. The pass is intercepted. The team with the ball scores.
Once the kids get used to the rules it is a pretty fast-paced game with a lot of changes of possession. The game is supposed to help coaches identify:
1. Athletic Kids (Speed & agility)
2. Which kids can throw & catch (Coordination)
3. Which kids are leaders.
4. Team Work
5. Conditioning (Most players love the game and don't realize how much they're running around.)
6. Throw in whatever else the coach may think he wants to evaluate.
I've heard of coaches that will let the players play the game while in helmets, shorts & shoulder pads so that kids can get used to throwing/catching passes while in their gear. I think mileage may vary on that one. The kids that are able to throw and catch well sans gear are still able to do so with gear on without any special breaking in period. There are versions where the players are allowed to run more. Coaches can see which kids have vision and moves. Usually called something like 'Hawaiian Football', 'American Ball', etc...
I still don't know of any that let the players hit each other. It's always 2h touch at the waist.