I'm sure for what we're doing you're gonna want a snell m-2000 or better. That bell has the highest ratings, as do the arai and shoeis.not sure about the one industries, although I think its in there as well. People with big noses generally don't fit the arais, and big chins/foreheads don't like the bells. Have you read Swaps articles in TWMX in recent months? He tried to move a loader tire with his head at 40mph a few months ago and gives his lid and leatte brace the cred for his being able to walk and talk today. These guys also did a review on a cheaper $150 helmet and failed it when they were able to break the jaw bar off with their bare hands. If I could afford it, and if I didn't have the big beak, an arai would be around my head. At up to $530 they are really spendy though too. My top three choices are the Arai, Shoei and Bell, I wouldn't buy a lesser helmet than any of these, and I've been on life support due to motocross related injuries, so take it from me. And sledding is just as dangerous.
Oh yeah shoeis web site has links to the snell foundation website, they list all of their ratings on there. Snell is the one to go by. DOT ratings mean little to nothing, they don't actually test the helmets for safety.