You guys also have to take into consideration that (and this is coming from someone who worked for 2 WalMarts back in my early days) all WalMart toy department's are run by varrying degrees and stocked by managers and stockers who are many times COMPLETE morons. There are exceptions, but in travelling this country up and down and all around and hunting toys for years, I find that no two WalMarts within a 10 mile radius are ran the same.
Case in point... my experience last night. The unopened case that I found last night at the first WalMart I hit was actually sitting on a BACKSTOCK pallet that they were in the process of readying to be pulled back to the stockroom to be filed away in the department stock bins. In fact, that WalMart didn't even have a spot re-pegged for the MM's. Had I gotten there even 5-10 minutes later it may have been back in the stock room to sit for who knows how long. But the second WalMart that I hit already had all of the figures stocked out on proper pegs (neatly even). Granted there wasn't a Fear Toxin Batman in sight, but I imagine the department manager or stocker, having shown the respect to the section that it deserves, probably knew that this figure was shortpacked and either purchased them for themselves (a practice I saw MANY times over the years working at WalMart) or called a friend who came and swept them up (again... sadly regular practice in a lot of toy departments across the globe).
So as many have said, be patient. And don't be too shy to ask if they have any in the stockroom. If you find a WalMart that has a peg sticker for them, pull one and take it with you. You can use that sticker to have anyone with a talzon (scanner) check their stock. And if they have some and there is room to stock them, then there should be no reason for them not to do so. There is no street date on the boxes (I have one sitting right here next to me) and these SHOULD be out on shelves. If you get someone who does not want to help you, ask to speak to a manager and then calmly state your case to said manager. If they won't help you, ask for their corproate information and let them know that you plan on contacting their superiors as well as let Mattel know that their store is not properly stocking their merchandise. This may sound extreme, but in hearing everyone badmouthing Mattel I have heard very little badmouthing of the stores themselves who many times are more to blame for crap situations like the MM's than the distributors.
End rant.