It’s a thing - “Leadman” - you do not only both 100s but the Silver Rush 50 (your choice of run or ride as I think those are on the same weekend) and the trail marathon and the 10K in the same year. Plenty of historical results in the google. Another informal but existing cohort would be those who have done both 100s but not in the same year. The Leadman was a thing even before the “sprint” events were added.
A bit dated, but:
http://assets.ngin.com/attachments/document/0020/5928/Leadman_All-time.pdf