I’m not aware of any, it’s the first of heard of the one you posted as well. There are forum members here with white gsds and they may have suggestions, though the thread title may not catch their attention. You might try PMing a moderator and see if they can edit in White gsds. Which ever breeder you decide to go with research them well. Health testing, titles, references, and so on. When breeding for specific colors the size of the gene pool is smaller so be careful and good luck.