Narrowing: highlighting "Narrow" lighter?

[Raffaele Ricciardi]

Hello there,

I'd like a more visual feedback when a buffer is narrowed than what is 
provided by the standard "Narrow" lighter.

I've thought about highlighting the "Narrow" lighter in the Mode Line, 
but as there is no Narrow mode and narrowing commands are defined in C 
source code, I can't find a way to do that without resorting to advices 
or writing a Narrow minor mode myself that manipulates the Mode Line.

Any suggestions?  Thanks.