If you want to find out some of the retro courses that have made the grade in Mario Kart 7, the latest update to the game's official Japanese website might throw some light on the situation.

The game's Shell, Banana and Leaf Cup courses and six battle arenas have now been unveiled, with selections from Mario Kart 64, Mario Kart DS and Mario Kart Wii all up there. If you want to see the original courses included in the game, the Mushroom, Flower and Star Cups are up there too, but do so at your own peril, though we're especially fond of the World 1-1 inspired course from Super Mario Bros..

[source nintendo.co.jp]