The Sacramento Zoo in Sacramento, California has one that is black and cream colored (no hint of pink or orange at all), but that's as close to black and white as I have seen so far.

On a side note, I was doing some biological surveys for my work in southeastern Arizona last month. Although (sadly) I did not see any gilas while I was there, the caretaker of the property I was working on said he had seen a black and yellow one crossing a road on the property. He described it as being bright yellow. All the field guides say they can be black and yellow, but I have never seen one like that before.