Andy it's a steely grey
http://www.usfreeads.com/360330-cls.html
The vets won't release info but the breeder looking after this is well known in the dog community for many years and will be talking to the Great Dane Club in Calgary.
I suppose its highly doubtful she'll go back there for a while, so she may be walking him elsewhere.
By the way, the one chomp complete took in the Ridgebacks entire hindquarters, from top of tail to scrotum. Pretty scary when you think of a smaller dog.