Apple and Sprint may have already completed work on a Sprint compatible iPad. 9to5Mac claims that the Sprint iteration of the iPad will join the rest of the current iPad line-up (GSM models and Verizon) before the holiday season. Given we've also heard confirmations of Sprint getting the iPhone 5, it would only make sense they'd eventually carry the iPad as well.
Sprint is the only carrier in the United States that still offers truly unlimited data plans. This may be a big draw for data hungry consumers that aren't currently happy with their tier happy carriers. 9to5Mac didn't seem to be able to confirm whether or not the Sprint variation of the iPad will support their 4G WiMAX network. The fact that Apple has made a separate version to run on Sprint instead of using the existing Verizon CDMA model may have something to do with 4G but at this point it's still unclear.
If Sprint ends up carrying the iPhone 5 and/or iPad this Fall, would you switch to have truly unlimited data again?