I wrote:
> Okay, the sentences listed below are the examples of
> "Nioi ga niou" (or "The smell smells"), once again,

I forgot to tell you one thing.  In these examples the
verb "niou" is intransitive.  So this is completely
another story than that you've shown at first.

In rather plain Japanese, the phrase should be replaced
by "nioi ga suru," but in a complicated sentence, "suru"
is a bit 'weak' to support/complement the meaning of
"nioi" in the distance.

For example,
花の匂いが、遠くから、かすかに、してくる。
is just fine, but
花の匂いが、遠くから、かすかに、匂ってくる。
is rather better in many situation.
-- 
Junn Ohta