I can be a little slow. Finally, finally I understand your answer. The mules aren't the new species. As you point out, they aren't fertile with anything. The only reason there are mules around is that people keep interfering with the natural mating preferences of the animals involved.
That horses and donkeys can produce mules shows that they are far more related than, say, horses and caribou. The most common case is that different species, if they can be induced to try to mate (or artificially inseminated) are totally cross-infertile. That the mules are themselves are infertile shows that horses and donkeys are no longer the same species.
That I agree with and appreciate the time and links you have provided. I see no contradiction between evolution and intelligent design. I think the controversy lies in the definition of "intelligent". Someone made a wise comment earlier that if the existence of "God" is ever proven beyond faith it will be science that proves it. I happen to believe in God and that he has one hell of a sense of humor. Thanks for the discussion.