I know the DS version of the Ace Attorney trilogy is very faithful to the GBA originals, yet they are not 100% faithful. The interface changed a lot and so did the music. Only the first case of the third game has been translated in english, and I belive it's more enjoyable than the DS version!
How hard would it be to insert the english, french or german script from the DS version in the GBA originals? There seems to be already existing tools to deal with the DS version, but they're quite unusable/incomplete.