An interesting game that never saw the light of day after E3 2003 is Nintendo's "Stage Debut". The game was intended to be the start of Miyamoto's digital avatar idea before it finally settled on the Wii as the Mii Channel.
Stage Debut featured compatibility with the GBA along with a new camera add-on. Like in the N64DD studio games you could have a picture of your face pasted onto a customized 3D model. Unlike the studio games, however, Stage Debut would give you a personality quiz to finalize your avatar instead of having the player finish the model up manually. Studio Debut also seems to feature less activities than the former games did, since the only shown activity appears to be dancing with various Nintendo characters (the other games had art and short-film programs). Most of these ideas from both games have been carried over to the current Mii creator programs and Tomadachi Life.
It's a shame that this game never got an actual release imo. It would've been pretty pricey, though, with all the peripherals that were required to play the game with.