bang carbon on a rock though, it gets a nice gouge; then what???

weight weenie or not i'd still recommend a steel or ti bike for mountain biking.

they might not be the lightest but they'll be around longer (and your really only talkin maybe a pound or two).

this guys stuff makes me drool.

http://www.blacksheepbikes.com/

but this guy will make you a nice steel bike at a great price (i got one).

http://www.waltworks.com/