Pure curiosity here. Today's horse on my horse-of-the-day desk calendar is an interesting-looking thing. The coat looks black, maybe VERY dark brown, but really, on the actual calendar even more than my quick snapshot with my increasingly moody camera, it looks legitimate black. The mane and tail are silver. I've never seen that combination of silver on black before.
There are couple possible silver WBx foals arriving this year. My foal due in mid-May by Sir Gregory - http://www.safyresporthorses.com/safyre.html - and another foal that is a 1/2 sibling to my mare who is in-foal to Commonwealth. She is due later in the summer.
The silver that was posted above that sold to Germany is also now in-foal for 2013 to a WB stallion.
If you would like to see more silvers variations, Silver Equine, also has a Facebook Group & Page. The group is more active then the page.