Recently, I replaced my car's deteriorated grey plastic push clips with new ones. I couldn't find originals readily for sale and decided to find an alternative.

They are Au-ve-co Products 21159 (66820-AX020)
Head Diameter: 14mm
Stem Length: 10mm
Fits Into 6mm Hole
Nissan 2005-On
Color: Black (it might be possible to paint or dye them)

Purchased from http://www.clipsandfasteners.com/
It is listed as A21159 Nissan Cowl Vent & Outside Mirror Push-Type Retainer.
The black fastener fits, is easy to remove (you just pull up the inner pin and the clip comes right out).

The flash shows the cross-hatch pattern in the top. It's not really noticeable unless you look closely.

The packing box.

 

Nice find.

Thank you sir.