A while ago the rumour was that the iPhone would eventually come to both Sprint and T-Mobile, possibly the iPhone 4S, and the latest word is Apple is currently in advance testing of a Sprint iPhone that has a physical design similar to the iPhone 4.

According to the 9to5 Mac guys, their sources say that the Sprint iPhone if actively being tested in Apple’s “Black Labs,” and also is with Sprint’s research and development and that the Sprint iPhone will not be 4G enabled.

Apparently though the unnamed sources do say that talk of a 4G iPhone continues, but depending on those talks the 4G iPhone may be delayed until quite late in 2012.

Furthermore Talk Android is also reporting that the Sprint iPhone is on its way and that the iOS smartphone will sport dual-band support for T-Mobile, and also claim that when it comes to newly released iPhone handsets Sprint and T-Mobile will alternate with Verizon and AT&T as to which carriers get the new device first.

Of course all this is unconfirmed speculation and thus be treated as such until such times as more substantial evidence turns up, but if true it does appear that Sprint at least will gain the iPhone at some point in the future.