I apologize if this has been covered, but I don't have the time to read through 10 pages of posts at the moment.
Now, let me preface my comment by acknowledging I am NOT a hardware engineer or even in the IC industry, but I do try to stay current with basic knowledge of CPU hardware and related stuff.. So don't quote on my anything as gospel.
That said, there are a few problems with this idea that a future iPhone would uses the Marvell chip, not least because Marvell itself doesn't list "smartphones" or "cellphones" even in their optimistic product literature as a recommended application.
More importantly, Marvell's "PXA168" (like all their app processors) is based on an ARM-compatible CPU core that is derived from the original Intel XScale architecture. Currently, it is only compatible with ARMv5 architecture which equates to the (older) ARM9 cores. Now that is not to say the performance is like an ARM9, just that it uses the old instruction set. The current iPhone uses a processor that has a standard ARM11 core and so uses the ARMv6 instruction set. I'm not positive, but I am assuming Apple's mobile OSX is compiled for ARMv6 (and possibly also uses a special SIMD/FP accelerator on the chipset) to utilize all the latest ARM features.
However advanced it may be, using a CPU that uses ARMv5 seems like a big step backward considering the latest version of ARM is the ARMv7 instruction set that is utilized by the "Cortex-A8" processing core -- the new hot rod of the ARM world. This is the core used in the new generation of smartphone processors from T.I., Qualcomm, and other key players.
I would be VERY surprised if the next iPhone did not use a ARM SoC that has the Cortex-A8 core since it seems like the logical next step. The only alternative I could see realistically is a newer, die-shrunk dual-core ARM11. Similarly, There is pretty much no way the next iPhone will use the next-gen dual-core Cortex-A9 as although the design is complete, it will not even be in a shipping commercial chip for another year.
More info on the Marvell PXA168:
http://www.linuxdevices.com/news/NS3542687598.html
Outline of ARM generations:
http://en.wikipedia.org/wiki/ARM_architecture#ARM_cores
P.S. anyone with advanced knowledge of the iPhone's low-level compiler architecture want to comment..