With Apple's recent embrace of Intel i5 and i7 processors in the 27-inch iMac, it's been considered a given that it would eventually use the mobile version (Arrandale) of these processors in future MacBook, MacBook Pro, and Mac mini updates. But one source, BrightSideNews, is claiming that Apple is refusing the Arrandale line of mobile processors, and asking Intel for a custom version of the chips.
The specific issue seems to be the on-board Intel Graphics chipset. Apple originally used the built-in Intel graphics capabilities in earlier versions of the MacBook, MacBook Pro, and Mac mini, but changed to NVIDIA graphics systems in later versions. The change to NVIDIA allowed better graphics performance than Intel was able to deliver with its on-board design.
Apple's rumored rejection of the Arrandale may actually be a rejection of Intel's reference mobile design platform (Calpella). Apple could still use Arrandale in a motherboard design of its own. This would allow it to use graphics processors from sources other than Intel.
The other option would be for Intel to produce a custom chipset design that would allow Apple to replace the Intel graphics chipset with one of its own choosing. Apple and Intel have worked together on custom versions of Intel processors and chipsets before, so I wouldn't be surprised to see a custom design being the direction Apple takes.
On the other hand, this is just a rumor. BrightSideNews doesn't yet have an established track record with Apple predictions or rumors.
My final thought. Apple needs the mobile versions of the i5 and i7 processors, and I expect to see Apple use some version of these processors in future laptops and small form factor Macs.