Most issues I've seen with carbon forks happens with the blades themselves cracking. I've seen pretty few issues with the steerer. Anyways just get a cheap no name carbon fork. There isn't much difference between a Giant or Leader or Trek or no name carbon fork honestly. There's a few dealers on ebay who even offer a 1 year warranty on all their carbon products, which could be nice since you sound abusive. I probably wouldn't be jumping any 3 stairs on any carbon road fork or any aluminum track frame though. Just a bad idea.