Although Apple was sure enough that the iPad mini would be a popular seller that it made the diminutive model the centerpiece of its holiday campaigns, even the prognosticators at Apple might have been surprised by the model's enduring demand -- and may have adjusted inventories and supplies to accommodate more iPad minis and fewer full-size iPads in their future mix, claims a new study by industry analyst NPD. The company has looked at display orders from Apple suppliers and believes the company changed its plans.