Systems that support/encourage different power levels in the party?

I was looking at the demo for Legends In The Mist, and though I didn't generally like the system much, I was pretty interested in how they encouraged playing games with different (in universe) power levels. The example LitM gave was Frodo and Gandalf being on a completely different power level in fiction, but having the same narrative power.

Now I realize that this is possible with loads of narrative systems, but I wanted to know if you people have any experience doing this in any systems? Or know of any systems which work particularly well for this concept?