In a comment to my last post, 54 mentioned that he remembered seeing a later prototype of the Black Hole with a smaller hole in the center. He followed up by sending me this picture of the wheel from a mid nineties issue of Road Bike Action. What a shame it is when those pesky laws of physics conspire to smash one’s blue sky concept. This prototype may have actually been rigid enough to work, but I seriously doubt that it was still a pound lighter than a conventional setup. It looks heavy to me, both visually and in weight. I would assume that the rolling resistance was greater than a conventional wheel as well. Oh well, at least they tried.
Also from recent comments, and anonymous reader points to better pictures of the Trek Lime prototype. For its intended market, I think the bike, especially the drivetrain area, looks pretty good. The way that the crank integrates with the chain guard is a nice touch. Speaking of the crank, notice that it says Bontrager and not Shimano. I am a bit confused. Are just the hubs and automatic shifters from the new Coasting group? I guess so. Maybe Trek had to design a new crank since they planned to integrate it with the guard.