Top 3-4. Haye is the former undisputed king of the cruiserweights and then moving up to fight champion 40-50 lbs. heavier; both of which have very good power which does not bode well for Haye's most difficent attribute. That shaky chin of his. Joe and Bernard are both great fighters but they haven't handled their business over the last 2-3 years like Haye would have if he beats one of the Kiltschkos. I don't see Haye beating either but if he did it would definately hold a spot in history.
He wont be undipsuted HW champ, even if he beats them both. Though he may as well be. He would be top 10 anyway. About 9 or 10. Slightly higher if he beat them both.