That will buy a WiFi only version, with a model with both WiFi and LTE connectivity going for $929, 9to5Mac reported Monday.
The 9to5Mac site said it received information on pricing from "a high-profile U.S. retailer."
Other than the increased storage capacity, the new model is rumored to identical internally and in its overall design, so the performance will likely be on a par with existing models, Slash Gear reported.
With increasing numbers of people using an iPad as their main day-in and day-out computer, it would make sense for Apple to increase the storage capacity to accommodate users who want their units to be able to hold more music, videos and photos.
Existence of a 128-gigabyte model was first suggested by a developer who spotted evidence of an upgraded model embedded in iOS 6 firmware, Slash Gear said.