Audrey Nicholls (Darelyn) mentions white curlies in her book and one predominantly white is preserved at a British museum. (I would have to look up what museum but you probably have a copy of Audrey's book.)
Here's the pic:
This guy looks totally curly: from the smooth face, etc. You can see the bonnet he has on his skull which is so correct for curlies.
There was also a pic on Ebay about 8 years ago of a white curly in the Northwest of the U.S. photographed in about 1900. Unfortunately, I could not bid high enough to buy it. I also could not bid high enough to purchase the pair of mittens from an early dog sled musher made out of curly skin and hair.
Some Great Pyrenees and Kuvasz historians indicate part of the development of their breed included crosses with English curly coated retrievers in Canada. Interestingly weird, huh?
"Cream" colored curlies are mentioned in some British writings of the late 1800's. At one time, a small white patch on the breast, rather than just a "few white hairs" was allowable in curlies.
I recognize some curly breeders believe any curly born with more than a few white hairs today is somehow the product of a mismating. But that would fly in the face of what Audrey Nicholls has written (and I don't believe anyone would deny Mrs. Nicholls was one, if not the preeminent, of the foremost experts on the breed in our lifetime.)
Regards from someone who owns a curly with quite a bit more than a few white hairs (and he has polka dots of black in his white patch--totally cool, at least to me....
J. Marti