Eh, I don't really think it would be that difficult. You'd have to tap in to the maplist array that is generated at the end of a match to add the "Hardcore" "Vanilla" or w/e suffixes. The FPI mutator loads specific mutators based on config files. In theory, you could just edit the configs via code as the map is selected, save config and it should load the mutator "game mode" you wanted. I don't know if it's possible, but if it was, that's how I'd do it.