Yeah, I've seen those at the track. They are useful if you are constantly changing out bar / stem assemblies, and don't want to have to constantly readjust the the headset. You still need to install a topcap, because open steerer tubes are not permitted for safety reasons. In the example shown by SB, you can eliminate all the spacers between the locking spacer and stem, but the SB spacer is not also an adjuster like the Problem Solvers part.