A series of photos posted earlier today by Boy Genius Report show an unreleased white iPhone 4 unit running on T-Mobile USA network. The device looks like an iPhone 4, although, as BGR notes, the proximity sensor looks different than the one shown in the (allegedly) final white iPhone 4 that’s been already sold in the UK. BGR claims the device, just like the Vietnamese videos from last week, is running an old and internal test version of iOS 4, confirmed by the several Apple internal and field-testing applications like Radar and Apple Connect or the preference panels to measure the performances of the device.

That’s right, you’re looking at photos of an iPhone prototype with T-Mobile USA 3G bands. The actual internal model is N94, and if you remember, the Verizon model is N92 while the standard GSM variant is N90. We have verified that the phone itself is running a test version of Apple’s iOS, much like the one we saw in those videos from Vietnam, and it includes internal Apple test apps like Radar and Apple’s employee directory app. Additionally, the front of the white iPhone pictured looks a little different from the photos of the retail white iPhone 4 that surfaced recently — specifically, the proximity sensor has changed on the retail version.

The model number of this white iPhone 4 is N94, the same one that months ago was mentioned in some iOS 4.3 code strings related to the A5 chip – also implemented on the iPad 2. Whilst rumors point to the white iPhone 4 finally being released on April 27th, the N94 model number and A5 processor indicate this might be an updated version of the iPhone 4 coming out later this year – perhaps the “iPhone 4S” select game developers are already testing ahead of the WWDC and the iOS 5 announcement. It’s also worth remembering that AT&T has filed documents in the US to acquire T-Mobile – if the two networks merge, the iPhone will eventually work on the old T-Mobile network (which currently has different radios and frequencies than AT&T). However, the acquisition is rumored to take several months before completion, and Apple could release an iPhone 5 / iPhone 4S this Fall that also runs on the existing T-Mobile network.

Check out the full gallery of leaked shots here.

A new report posted by Joshua Topolsky at This Is My Next seems to contradict the rumors we’ve been hearing in the past weeks in describing the next-generation iPhone – so far dubbed iPhone 5 – as a complete redesign of the existing iPhone 4 hardware. The report comes with a mockup based on sketches and descriptions the website received by multiple sources over the past weeks, and shows a dramatically thinner device with a “thick to thin” design from top to bottom similar to MacBook Air’s main body, and a larger multitouch display set at approximately 3.7 inches. The change in size would allow Apple to keep the existing Retina Display branding with a drop to 312ppi (iPhone 4 features 326ppi, and Apple claims a “Retina Display” can be called so starting at 300ppi on an iPhone), and it’s something that’s been rumored before and even spotted in allegedly leaked Apple design documents.

Our sources say the new model (or at least one of the new designs in testing) looks “more like the iPod touch than the iPhone 4.” The phone will be thinner than the iPhone 4, and may have a “teardrop” shape which goes from thick to thin (something along the lines of the MacBook Air profile).

This Is My Next also claims the Home button will become larger, doubling as a “gesture area” for a series of multitouch commands likely inspired by the ones introduced in the iOS 4.3 developer betas. Apple was rumored to be considering an early departure for the Home button, but the website claims the company has been playing around with various prototypes and design iterations, and one of them indeed sports a larger, redesigned version of the Home button. With a larger, almost edge-to-edge screen, Apple is apparently also experimenting with the idea of earpieces and sensors hidden directly behind the display’s glass:

Furthermore, we’re hearing that the screen on the device will occupy the entire (or near to it) front of the phone, meaning almost no bezel. Our source says the company is doing very “interesting things” with bonded glass technology, and has been exploring designs where the earpiece and sensors are somehow behind the screen itself, making for a device where the display is actually edge-to-edge.

Other details reported by This Is My Next include a “swipe area” for NFC capabilities, inductive charging and world-phone functionality with a global CDMA-GSM chipset. Again, these features have been in the rumor mill before, but This Is My Next’s report is mostly interesting because of the design speculation included in the article that contradicts several rumors we’ve recently heard. And even if the design may never make it to the final version of the iPhone 5, TIMN says it’s being tested by Apple:

The versions of devices our sources are seeing could be design prototypes and not production-ready phones. Still, there are strong indications that Apple will surprise a public that’s expecting a bump more along the lines of the 3G to 3GS — and this is some insight into where those designs might be headed.