Ebikes.ca does some custom spokes. I got black from them.
your best bet is to have your current rim laced onto the motor. If you're mechanicly inclined, its an easy enough job, but if not, a Bikeshop shoul;d be able to do it.
Ebikekit.com sells the all black 9Cs, with there logo etched on it in silver, but its glossy. for that flat black look, you will likely need to get the motor powdercoated.
I'm running an all black wheel, but I painted mine with enamel, then laced it in a black DH rim myself after having the spokes custom cut.