I don't know if you'd count these one-off experiments in the same league as making aircraft that you can actually turn a profit manufacturing and operating. That game seems to have dried up at about the size and speed of modern jetliners, given the issues we've had with operating supersonic commercial aircraft.

I'm sure somebody in a lab somewhere can make a single processor that's ridiculously fast compared to anything you can buy, but being able to manufacture usable, reliable CPUs in quantity and cheap enough to turn a profit on selling them is a whole 'nother ballgame.