While this doesn't confirm the presence or development of new devices, it's worth noting that the maximum storage option that Apple currently offers for iOS devices including the iPhone and the iPad is 64GB. With the average app size increasing (especially after the launch of the Retina display iPad), apps are taking up a large part of storage space, which implies that space for user data is shrinking. So it makes sense for Apple to introduce devices with increased storage space.
Earlier this month, it was also reported that developers are seeing presence of new iPhone hardware and iOS 7 in their usage logs. The report had claimed that developers were seeing a new 'iPhone6,1' identifier, powered by a device running iOS 7, in their app logs, with the app requests originating from an IP address leading to Apple's Cupertino campus. It would be interesting to see whether Apple will launch new storage options for current devices or would keep it for devices introduced in the next refresh cycle.
(Image Courtesy: iDownloadBlog)