... I think MRVL is supplying something, but I'd think maybe networking chips rather than the CPU. Aside from the other reasons to suspect the CPU is ARM (including your posts regarding Gruber and his observation that Apple considers ARM expertise a plus for an iPhone position), ARM claims Apple's whole iPod line as customers for ARM.
Not sure whether these are entirely up-to-date or whether they just reflect a comprehensive historic customer list, but if it's current, Apple could be moving to all-ARM until Intel coughs up a better-performing embedded chip. It's interesting that Apple is wiling to use alternate mfgs as a threat with its CPU supplier; the high-level Cocoa frameworks on which Apple's apps are built and the ability to compile for multiple architectures are a real plus, apparently.
I guess Apple is tired of being enslaved by any chip fab shop.