Wont happen, it's somewhat analogous to playing a Wii game on a gamecube. The underlying hardware may be very similar, identical in some cases, but the DSi has a few extra bits and pieces that DSi specific games will use. Think about it - if the game were able to run on a regular DS, surely that's the format it'd be released since there's already millions upon millions the bloody things out there?

well, the ds light doesnt support the dsi channel, meaning it cant download the games, but if a dsi ware game makes use of regular functions, instead of the camera and stuff, then a dumped game should be playable on the dsl.

Still it's very, very unlikely to ever happen. Even if the game itself doesn't use those features, that doesn't mean it hasn't been built upon libraries that expect them to be there.