exotic methods of heat-shielding
I have worked on designs that use water cooling (with the water dumped overboard). Obvious weight penalty, but for highly limited areas like leading edges, works like a charm, and very simple. No recirculation, and the heat gets dumped overboard (where the heck would a recirculating refrigerant system PUT the heat?)
I have also worked on designs that pump gas or liquid into the bow shock to reduce heating on the structure. Works for drag reduction on launch, too.