IMO, the only "weakness" of a carbon steerer comes from the fact that you have to clamp the stem onto it. It is easy to damage the steerer by over tightening the stem.

As for a sturdy fork recommendation, i would recommend the Alpha Q CS10.
http://www.truetemper.com/performance_tubing/cs10.asp
Alpha Q is the fork brand of Truetemper (the steel tubing company). It has carbon blades with 1 1/8" Truetemper OX Platinum steel steerer. Very stiff and pretty much bulletproof. Close to the same weight as most carbon/aluminum forks.