Apparently Cannondale does.
From Velo-news
The head tube houses a proprietary oversized headset and 320 gram fork. The fork's steerer tube tapers from a large 38mm at the crown to a standard 11/8 inches at the top, while the head tube's diameter remains constant throughout. Because of the enlarged sizes, Cannondale had to play a role in making the front end's components compliment each other both aesthetically and functionally.
Cannondale’s fork tapers from 1.5 inches to 1.125 inches. Cannondale has done it’s design homework to seamlessly integrate the system’s fork, stem and headset.
FSA makes a proprietary headset with an oversized lower bearing, 1 1/8 inch top bearing and a finessed top cap. Cannondale enlisted Control Tech to make a proprietary System Six stem. The stem is made from carbon fiber with alloy inserts for the steerer and bar clamps, it will be available is 80-120mm sizes. The steerer will also accept any conventional 1 1/8 inch stem.
From Velo-news
The head tube houses a proprietary oversized headset and 320 gram fork. The fork's steerer tube tapers from a large 38mm at the crown to a standard 11/8 inches at the top, while the head tube's diameter remains constant throughout. Because of the enlarged sizes, Cannondale had to play a role in making the front end's components compliment each other both aesthetically and functionally.
Cannondale’s fork tapers from 1.5 inches to 1.125 inches. Cannondale has done it’s design homework to seamlessly integrate the system’s fork, stem and headset.
FSA makes a proprietary headset with an oversized lower bearing, 1 1/8 inch top bearing and a finessed top cap. Cannondale enlisted Control Tech to make a proprietary System Six stem. The stem is made from carbon fiber with alloy inserts for the steerer and bar clamps, it will be available is 80-120mm sizes. The steerer will also accept any conventional 1 1/8 inch stem.