This strikes me as a pretty bad idea. Plenty of today's biggest games could not really be ported while staying true to their original vision.....Mirror's Edge, Gears of War, Assassin's Creed, Dead Space....stuff like that just isn't going to translate in any proper way. You could turn it into a sidescroller or something like that, but then it really just becomes a generic licensed sidescroller, doesn't it? Nobody really plays those games for the story/IP, so it's not like you'd get much satisfaction in seeing the universe expanded in a DS sidestory.
Even competent down-ports like Ninja Gaiden: Dragon Sword just tend to make me wish I was playing the proper console version.
Somehow this reminds me of the "Wouldn't xxxxxx franchise be much cooler if it was on the Wii?" threads that incessantly plagued the forum 12-18 months ago.