I don't know about you guys but a carbon steering tube on an off road bike scares me. It's not like a road bike. How much weight do you save with a CF steering tube over a steel one? At best a couple of ounces.
Tim
Oh, I'm not thinking a carbon steerer would be the way to go at all - I agree that it'd probably be a poor choice for cross. I'm thinking an alloy steerer would probably save some noteworthy weight over a steel counterpart.