Today, Sprint's President of Network Operations, Steve Elfman, commented that Sprint is going to bring its new 4G LTE to its Prepaid Divisions in the future. Not only that, but he took a moment at CES to confirm that they plan to keep unlimited into the future as a way for Sprint to differentiate itself from its competitors.
Sprint will likely wait to bring LTE to prepaid when it's LTE network is built out much farther, as well as when the device line up can support it. Especially with entry level LTE devices.
Sprint's first devices expected this summer will be flagship and mid-level price points. However, Sprint has announced that they will be releasing between 12 and 15 new LTE devices in 2012. It's also anticipated that Sprint will release 4G LTE devices to their MVNO partners at some time in the future.