We’ve received a slew of e-mails from irate readers who had placed pre-orders on Walmart.com for the Blu-ray/Standard DVD combo pack of Iron Man 2 for $15. Yesterday, they received e-mails from Walmart telling them their orders were canceled “due to limited availability.” And yet, Walmart.com still lists the product as being available; you just have to pay $10 more if you want to buy it. [More]