I'm hoping to thru-hike in 2008, and I bought the ULA Helix "potty trowel". I got the smallest one, 55 cm. I tested it last week in the snow and found that I can self-arrest well enough with it, and chopping steps requires a different technique with a shorter axe and a much lighter head, but it works. http://www.ula-equipment.com/helix.htm