this one for the PS3 is actually getting veery close http://www.gametrailers.com/video/e3-09-mod-nation/50294 edit: a second video, showing the track editor: http://www.gametrailers.com/video/e3-09-mod-nation/50295
i dont know if this was mentioned already. http://kotaku.com/5274698/xbla-getting-free-dlc+supported-racing-game http://www.gametrailers.com/video/e3-09-joyride/50001