It has the hardware capability; actually for a properly done port it can look better. SM64 DS looked much better than the original graphically. Diddy Kong Racing DS is another example. I think Metroid Prime Hunters couldn't have been done on the N64 at all.
But there is no way to play arbitrary games because Nintendo hasn't created a VC for the DS yet. And if they did it would [this is me speculating] be for GB, GBC and GBA games only to not overlap with the Wii market.







