User Rank -or- User Percentile Rating
Entirely editing my answer to try and make sense here ...
Wikipedia page on Standard Deviations.
I suggest that we display a value that represents the number of standard deviations from the norm that a user is.
The Y axis is the % of users with that reputation score, the X axis plots scores from 0 to n. You could then determine where the user is in terms of rarity with regards to the entire user-base, rather than looking at a reputation score that a large volume of users could be in. So I could show up as 101 rep, and we can identify just how rare (or common) that range is in the deviations of users on SO meta (about 8,750/21,000 = 41.7% have a lower reputation than me), where as someone at 0 would be
This is similar to how people are ranked as "genius" with IQ scores, as they are in the top 2% of IQ scores.
We could give users titles for being at specific deviations.