I've seen weight bars advertised as snow thrower accessories. I slapped 25 lbs to mine with some wire ties through a 1/4" hole and it really helps keep the front end down. It has less tendency to climb the packed snow base and it also helps keep the front end down when going uphill. If you have a snow thrower and you've ever found yourself pulling up on the handles to put more pressure on the front I recommend you try it. I'm going to add about 10 more pounds next time I use it.

PS -- the snow thrower cab is also a nice accessory. It weighs only about 2 or 3 pounds (so it dosn't upset the balance of the machine), and keeps me a lot warmer when the wind blows. Also keeps any blow-back out of your face. If you shop you can find them online under $100.