i saw on the Wiire that there was this trailer thing and it had the galaxy game and mario and luigi getting a star and it turned out to be a ds. and the jumped inside of it and then they came out and it was displayed on a DS and ther wher playing galaxy on the DS. and ofcourse the graphics where a little bit worse than the Wii's. (you know DS graphics) but the title said Super mario Galaxy DS. i will get the video link for you guys. i hope its not a nother rumor like Halo DS was. lol.
i think this is it
http://www.gametrailers.com/player/usermovies/143887.html - (WARNING: Contains some spoilers from Super Mario Galaxy, do not watch unless you've played through the game.