JD,
I've heard a lot about coy-dog crosses over the years, and I know it's possible, but out of all the many hundreds of coyotes I've killed, as well as many hundreds more I've seen others shoot, I've yet to see a coyote that looked like it had any kind of domestic dog blood in it.
I'm not sure if it's just really rare in the wild, or if the coyote genes are just so strong that they maintain the coyote look. Knowing a bit about coyote behavior, I'm inclined to think that it's just a rarity in the wild.
Not that it doesn't happen, mind you, but I think it's very rare.
I've seen pictures of a black coyote that was killed. Also one that was sort of a chocolate brown. It's been a few years, and I don't remember where they were taken, but they were interesting pictures. Around here we have the typical redish, yellowish, and even some silver tipped coyotes, but I seldom see any variation of that; even though domestic dogs are frequently loose in areas where there are plenty of coyotes.
Who know for sure, though?
Daryl