Yep, Nintendo Power have proven the rumour was spot on and a new Epic Mickey game was most definitely coming out for the 3DS. See here:
Yes it’ll be called Epic Mickey the Power of llusion and will be coming to 3DS. Also seemingly of note, I guess the Mad Doctor ends up with the main villain role in these new games? Because he’s featured rather prominently above and with the Phantom Blot out the picture it only makes sense for him to be the next Big Bad, right?
Still, rumour was spot on. My E3 post is coming more true by the minute!