Yeh M1.3 to 1.4 sounds economicaly feasable but Im certain the aging "anti-Concorde" bozo-rabble of the early 70s and there descendants will reawaken if the SC is redesigned for flight above Mach 1. And unfortunatley those countrys which would have a strong market for such an aircraft also have these "rent-a-bozo" outfits as political base for Green political partys, who only survive and florish on the gullability and unedjamakation of the idealistic Unwashed.