Source list with counter next to item title

FROM : GbT
DATE : Mon Nov 19 10:14:30 2007

What's the best way to have a sourcelist with a counter next to the title as
you see in many apps (Mail and other indie apps)? I mean the grey
circle-ellipse with the number of items written inside it.
Maybe I need to subclass NSCell and override the drawInteriorWithFrame:
method, but how could I set the counter from, let's say, an arraycontroller?
Would it be possible using bindings?

Who could give me a detailed explanation of the besth method to achieve
that? I read other posts and articles about subclassing NSCell but none of
that seems clear and easy to do.

Thanks a lot.