With iOS 6.1 hitting its 5th beta 9to5Mac is reporting that the code of the OS indicates that Apple could be preparing to launch a 128GB variant of the fourth generation iPad. The report is pretty clear-cut when it claims this and claims that this will not be a new iPad model, but would rather be a new premium SKU.
The report suggests that the code suggests a new ‘Ultimate’ model for both cellular and Wi-Fi only variants. This report matches previous findings that have suggested a 128GB variant of the same. That said, it is also clarified that this model could be specific for government agencies or could be for just internal testing purposes.