Honestly I'd say Dunalino or Silver Dunskin. But one of the parents would HAVE to have the creme gene. I don't suppose you have the papers do you? If he has them. Because while silver and dun can be pretty tricky to detect in some cases and silver doesn't show up on chestnuts it can look like it skips a generation. Creme really isn't that tricky though, so its usually on papers. This is not a black based horse, I can say that with a lot of confidence. Either bay or chestnut. Though I'm leaning more towards the bay side with Silver Dunskin. Dunalinos don't usually have dark primitive markings.
So I'm going with silver Dunskin