My blog profile picture is a Desert kangaroo rat, Dipodomys deserti.  I rendered it using photoshop and the process was inspired by Corlis Schneider.  
Rendering like this is similar to the way I work with traditional media.  I chose a base color and pixilated and blurred it.  Then I used a wacom pen and the brush tool to add each hair individually.  

Kangaroo Rat

Kangaroo Rat

Kangaroo Rat

Kangaroo Rat

Kangaroo Rat