Well some supersonic designs are on the table and certainly the pilots aren't going to be sucking on o2 for 6 hours...I suspect the cockpit will be it's own pressure vessel inside of another vessel......
Also hear of eliminating windows, going to all cameras...ending the window blow out/bird strike issue.
Either that or everyone is wearing suits like in the U2....
But as was said this was adressed for the guys flying the Concord.