Charmandersrule: Do not count on it... In fact, I would count AGAINST it. There just is not enough horsepower in the DSi... The main processor may be double clocked, but most add-on chips are clocked at 4x or more of the original SNES cpu. The main SNES proc is clocked at 3.78mhz, but, for example, the SA-1 chip (used in super mario RPG) was clocked at 12mhz and was a slightly more complex chip (as well as containing additional RAM). FX chips (like those used on later 3D snes games and Yoshi's Story) were clocked at 20mhz.
And as I mentioned in a previous thread, it's not just a matter of emulating the chip, but successfully syncing the various "chips" together in software. That alone will probably take as much in the way of resources and ingenuity as reworking the added chips that need emulation.
I'm not saying that it's impossible... but it is increadibly unlikely to get running at full speed or even half speed on the DSi.