To me danny it sounds just like extreme overheating of the pads. If the fluid boiled/overheated then you get a squishy pedal (going to teh floor in extreme circumstances) but if its pad overheating then you get a hard pedal. If the pads are heated to outside of thier operating range then their friction properties change considerably! Like with cold carbon metalic (race) pads untill they are fuckin hot they do bugger all!! In the same way if normal spec pads go over a certain temp tehy do bugger all!!!! Ive had it a couple times, but not quite to that extent.
I expect that afterwards teh brakes were not on 'top form' especially the next day, as when you heat em up this much they get 'glazed'. But a good average run with a few hard stops will de-glaze them pretty well.
If you totally overheated them, then they disintegrate!!! lol so take it easy danni, dont wanna see a KA Saxo combo any time soon!