While this isn't exactly the place to discuss theories and such, there are actually a couple flaws in your argument. The first one being that Totosai doesn't like Sesshomaru and therefore refuses to make any sword for him period. The second flaw in your argument is that while Sesshomaru could have a sword made from one of his fangs, it still wouldn't be as powerful as one made from the fangs of his father, as he was much more powerful than Sesshomaru as a demon.