Expressing levels of achievement/reputation (eBay stars)

We all know eBay stars - different stars denote accumulated reputation
or "feedback score".

I like Ebay's colored star icon system because it's more elegant
and more subtle than, say, a "five star" hotel/restaurant system.
It's more like a karate belt color ladder.

But can levels be expressed in yet subtler ways? What other graphic
elements can be used?