A large part of that delay may have been the redesign of the chasis - something that won't be a factor this time around. Anyway, I understand that releases don't obey a law of averages, but we have to be realistic that 11 month updates are far too slow, especially when your competitors already have Penryn chips in their products. All I'm suggesting is that competitive pressure will likely keep Apple from waiting too much longer than 7 months.
I did say "other than bus speed." I recognize that bus speed is important, but Penryn without Montevina is still a good step forward on its own. Furthermore, even with the iMac's small frame, it can still hold a more powerful fan than an MBP. Speaking only comparatively, heat is less of an issue in the iMac. And surely you agree that power consumption and wimax are also less important in the iMac than the MBP.
Unlikely. Intel has a clear roadmap to help their OEMs. While they will certainly break with the roadmap for some devices, why would they do that for a consumer level device that can fit full-sized chips? To deviate from their roadmap is expensive, so why would Apple want to raise the cost of their consumer computer unless there was some highly specific need for a custom chip? Instead, Apple will no doubt buy the chip that allows them to get the healthiest profit margins, and those will come from a chip that Intel can mass-produce and sell at lower wholesale prices, not a custom chip that deviates from the roadmap.