are you sure he is 30inches at the shoulder!? and if he is then 35 pounds is grossly underwieght lol. my aussie is 18.5 inches at the shoulder and she is very lean at 35 pounds. so something isn't quite adding up with your boy.
my guess is Siberian husky, border collie, Terrier
my guess is Siberian husky, border collie, Terrier