Source: me (several years now complete w/ PhD), my cohort in my program, and my PhD-earning friends outside my field.
I wonder if they exist and if so, how rare.
I suspect it's extremely rare or non-existent for an athlete who holds another full-time job up to the selection time to get selected into a US Olympic swimming team, for example.
"But if you want something extraordinary, you have two paths:
1. Become the best at one specific thing.
2. Become very good (top 25%) at two or more things.
The first strategy is difficult to the point of near impossibility. Few people will ever play in the NBA or make a platinum album. I don’t recommend anyone even try.
The second strategy is fairly easy. Everyone has at least a few areas in which they could be in the top 25% with some effort."
See also https://www.skmurphy.com/blog/2010/04/18/jack-of-all-trades/ for an exploration of how deep knowledge of multiple domains enables opportunities for knowledge brokerage.
So 0.0001% of all university students, and then... work three times as hard as them ?
Working harder gets exponentially harder the harder you work. So... 0.0000000000001% of all students then ?
And now, in your application form for a PhD program, you want to convince an employer that they should hire you because you think in you are in that bracket, without any proof that backs it up, even though if for some reason you are not, things catastrophically fail for your employer ?
Yeah good luck with that.