I found them at Wal-Mart this past Wednesday. I had to pop in to pick up something and I always check the toys and found them! Maybe try during mid week.
Be wary if you ordered from Toys R Us... I had a shipment of 4 different shells arrive today. 2 are the wrong ones, and 1 is a duplicate. So now I don't know what to do with the duplicate shell because they want me to pay to ship it back which seems pretty wrong considering it's their error and the packing slip does not match what they sent