Two pictures which are supposedly taken from a Toy's R Us pre-order leaflet of Pocket Monsters Platinum have recently surfaced.
On the picture from the leaflet it states: "For hints as to the identity of the silhouettes, check the leaflets attached to the products' packaging. Tools/Information related to the sihouetted Pokemon will be delivered Sunday, Sept. 28 thru Tuesday, Nov. 4."
It's possible that these silhouettes could be confirmed next week when the latest Corocoro is released.