Long Zheng at iStartedSomething has gone through those device renders by Nokia with a fine toothed comb and has turned out some potentially interesting information.
In short, there are too many tiles on the screen for the Nokia devices and when he looked closer, he notoiced that the screen resolution is similar to that of other Nokia phones. From this he extrapolates that perhaps Nokia will be reusing their own hardware for their Windows Phones, to reduce production costs and speed, and that may be the reason for the change.
Our thoughts? Maybe, but we're erring on the side of no.
As more details have come out from the Nokia-Microsoft partnership, what comes across is how fast it was thrown together (in fact, as far as we know, the deal is not completely signed off on). From Elop himself during last night's Q&A, he mentioned how it was only Thursday that the Nokia board gave their permission for the Microsoft deal. That's some mighty short timing and we can't help but think that these renders, while very nice, do not actually tell us much about the design intentions of Nokia and Windows Phone.
Still, rumors are floating about a revision to the chassis requirement, including new resolutions. But we think it odd that this news would first show up in some quick phone renderings. We'll keep an ear our though for more info.
Update: Absolutely not. In speaking with some higher-ups at Microsoft, we can definitely say there is no new screen resolution, nor is Nokia changing that area. It was indeed a mockup thrown together quickly and is not meant to respresnet any final product. But, we can confirm that Microsoft and Nokia on the engineering level have been working together "for some time" which should speed up device-to market time.