Incendia Castle, a classic Mario Kart Wii custom track, is being remade for Mario Kart 8. The modding community for Mario Kart 8 is still in the early stages, but major steps have been made to make playing custom tracks a reality. MrBean35000vr and Chadderz are leading the way, having already discovered the DLC placeholder files along with changing textures and importing models into the game.
MrBean35000vr recently uploaded a video showcasing his progress on recreating Incendia Castle for Mario Kart 8. The track is still early in development, so keep that in mind as you take a look at the video below.