So... here's the thing.
AKB48+Me is a Japanese-only 3DS title that focused on the popular J-pop band, AKB48. In the game, the player's Mii can also join in, hence the "+Me" part. I know where all the Mii data files are, except - get this - there seems to be over 500 Mii data files in this game. That's a lot!
Now, I believe many are duplicates... but there's only one way to find out. I'll get to this game eventually, but it'll take a while!