IGN has an interview here with Kazunori Yamauchi where he is asked a number of questions on what the future holds for Gran Turismo fans. Some of his answers are rather coy and he evades the questions over the recent rumour of a track editor and the number of discs GT5 will ship on but in answer to the question of whether motorcycles could make an appearance in GT5 he says "If that's what users really want in the game, I think that's a possibility. Or we could consider making a Tourist Trophy 2 as well."