And you won't any more, though there were some in the past. The other option is to buttress a carbon steerer internally with a CrMo sleeve extending a few inches below the headset. To work right, it should be a close slip fit and bonded to the inside. It will add some rigidity, but mainly act as a safety net in the event that the carbon fails.

You could also do the same the old fashioned way, with a wooden dowel rod, which is what they used to buttress the bottom of steel forks for decades.

So you do have options, if you have an absolute need to go that high, but you have to do it in a way that protects you from disaster.