I've never seen it, but in this last week (yesterday and today, really), I've gained 49 reputation; meaning I would've expected to see something similar to the example in the title of Jeff Atwood's whatever-you-call-it. I have a feeling that it's only if you're past a certain reputation, do other people see it, but this made me even more questioning if I would see that same thing on my own profile if I was signed in looking at my profile.
As Catija mentioned in the comments, you need 200 rep to start showing up in the reputation leagues. That's why you're not seeing this on your profile. In the right hand side bar, under the charts breaking down users by rep, you'll see the following note:
users with less than 200 reputation are not tracked in the leagues
To answer your direct question, I also don't see this on your profile, but I do see it on mine.
The banner shows you what your current highest ranking in the leagues are. For Jeff, it's 0.03% overall. For me, it's 9% this quarter.