The iPhone--love it or hate it--has played a huge role in redefining the entire smartphone genre. And since it will continue to do so, the information we can glean about the next device before it launches is interesting (you can bet Google, HP, HTC and a bunch of others are trying to do the same thing). So while the next iPhone isn't expected for at least a few months yet, there's already plenty to talk about:
Curved glass screens?
This is the hottest rumor, hinting that while we expect many of the upgrades to the iPhone 5 to be cosmetic with some spec-bumps, Apple  may be considering  taking a lesson from the Nexus S's design. For this Android unit the screen sported an unusual curved glass frontage, a big novelty for such a device. Research has suggested that users felt a curved screen enabled a more natural touch-interface experience--something that conceptually makes a certain amount of sense because our hands and fingers do move on a radius rather than in straight lines (and this is part of why typists get RSI).
Apple's reported to have bought  several hundred specialized curved glass-cutting machines to enable the design feature--side-stepping any issues that may come from ordering curved glass from suppliers more used to cutting flat panels. This is exactly the kind of smart investment Apple seems to have been doing more and more of in its manufacturing, and it's possible thanks to the company's massive cash reserves.
Do we think this is likely? It's surprising, and yet so many different parts of the rumor seem to make sense--Apple has expertise in curved glass frontages thanks to two generations of the previous iPod Nano. Plus it's a design tweak that only enhances the existing iconic iPhone format, rather than subsuming it.
4:3 iPad-like screen?
Here's one we haven't heard before: The next iPhone may , as well as a 4-inch size, be getting an aspect ratio tweak to 4:3 shape (a multiple of 1.33), exactly the same as the iPad. The current iPhone screen has 960 by 640 pixels at 326 pixels per inch--that famous "retina" resolution, but iOS developers have to rewrite their code to support the iPad's 1024 by 768 screen. Could Apple actually have squeezed a screen with the exact same resolution into the new iPhone? It would make excellent technical sense, considering the iPhone 5 will have the same CPU as the iPad 2, and thousands of developers may be hugely relieved--giving iOS App Store a big nudge just as the battle with Android is heating up.
No LTE, but world phone chipsets
Speaking at the Reuters Global Technology Summit last week, Verizon CFO Fran Shammo dropped several interesting hints  about Apple's next smartphone. We can probably trust a Verizon senior exec to have insight, courtesy of the fact Apple broke with its usual habits and designed a custom iPhone 4 version for the U.S. cell phone giant that used its non-standard CDMA 3G technology. Shammo suggested the next iPhone may shun LTE, but it will contain baseband chipsets that support both CDMA and GSM connection standards. The phone, as a result, will arrive on both AT&T and Verizon at the same time in the U.S.
This agrees with several earlier suggestions  that Apple was adopting a Qualcomm-supplied baseband chip for the next phone, one that specifically included the two connection protocols. This could give the phone true world-phone powers, and possibly even allow it to be used on T-Mobile and Sprint systems in the U.S. (an interesting move, given AT&T's maneuvers to purchase T-Mobile USA).
It could also explain the delay until later in the year--the Verizon iPhone 4 only arrived in the new year, and if Apple released an iPhone 5 in the usual Summer timeslot, this could result in severe buyer's remorse in millions of new iPhone owners.
Arriving months later--maybe late September?
Concerning the arrival date, we're now wondering if the iPhone 5 may arrive even later than we suspected--perhaps even in late September. Piper Jaffray analyst Gene Munster, a well-known Apple commentator, has been examining  Apple's Eastern supply chain and notes that parts orders are being placed "several months" later than usual, a phase that implies a pretty big change to Apple's ordering schedule. Munster has also reiterated the 4-inch screen rumor, and suggests that while there are several reasons for the delay, Apple may be holding back because it hasn't yet fully baked its next-gen OS.
Outlandish rumor: Augmented Reality baked in at chipset level
Chip maker Qualcomm has been working on Augmented Reality powers for some time, and an outlandish rumor  is suggesting that while Apple won't be using Qualcomm's Snapdragon CPU for its future devices (its own ARM technology is too precious to just give up), it may be using Qualcomm's AR solution at a deep level of integration in iOS--a trick that could add serious new powers to the iPad and iPhone and distinguish the devices from the competition.
UPDATE: First believable hints on shape, size from Orange France
France's Orange network CEO Stephane Richard has revealed details  about what he knows of the next iPhone revision in an interview. Richard notes the phone is thinner and smaller than the existing iPhone, and the radical design was made possible due to a brand new SIM card standard that's even smaller than the micro SIM used in the iPad.
This backs up a number of rumors we've heard previously, including Apple's efforts at legally requesting definition of a new smaller SIM format. Richard suggests the new SIM is a design compromise, developed after a disagreement between Apple and its numerous carrier partners over Apple's plans to include an electronic SIM solution.
Richard's word carries some weight, as France is a lead nation for Apple's iPhone releases, and Orange sells the iPhone in 15 nations--second in handset sales only to AT&T. But the rumor will re-ignite debate about a dual-path upgrade for the iPhone, since this sounds a lot like an iPhone "Lite," since we all know that one way to make things cheaper is to make them smaller and lighter.
Photo of back plate?
Potentially at odds with Richard's words is  what's rumored to be  the first "leaked" external piece of the iPhone 5--a white backplate that seems to be of glass, and which sports the separate camera unit and flash position we'd seen before. It's hard to say but it does look slimmer than the iPhone 4's backplate, but without any additional data we can't draw any conclusions.