I suspect any new hypersonic (or even supersonic) Part 25 aircraft would have to be certified based on the probability of sudden cabin depressurization being extremely remote (10-9/hr. in cert speak) - any other solution would be unworkable (passengers in pressure suits...). The Concorde couldn't be certified under todays rules using the small window solution.
That might well mean no windows aside from the flight deck, multiple redundancies in the pressurization systems, and greater margins on the structural side of the pressure vessel. Even then, there is a regulation regarding having to withstand a certain size fuselage hole (i.e.. bomb blast) that would need some sort of Equivalent Safety Finding (ESF).