If the DSi is somewhat like the Wii...

Then will the DSi support .wad files and be able to play homebrew without a flash card? I've been running this through my head for a while. Also will there be a game for the DSi that will be needed to perform this hack(similar to Twilight Princess)? maybe a rom? Or a downgrader like the PSP to prevent flash carts from failing? ???So many questions, not enough answers.

I doubt it.

Just buy an DSi flash cart