Looks like the HK Store announced some content early again!
The best thing about Sackboy is that you can make him look and act exactly how you want. Buy it and you can get Sonic the Hedgehog, Tails, Knuckles, Werehog and Dr. Eggman Costumes.
Around Christmas last year we got the Metal Gear Solid pack for LittleBigPlanet, and this year it looks like we are getting at least some Sonic Costumes. Hopefully this is part of something more, but licensed costumes are always ok with me.
The Release Date is set for 12/17 and I am sure MediaMolecule will update us when we get closer to that date.