There are only 3 ways the genes combine to produce Yellow dogs. The inability to express a dark coat is the recessive Expression gene, so if there are two lower case e, the dog will be yellow.

Note that the double recessive dog will have a chocolate coloured skin (ie. a yellow dog with a brown nose). This combination is not allowed under the "breed standard" rules, which means you could not show this type of dog as it would be disqualified.

I think they look quite nice, see a picture on this Web Links page.