New iMac: Montevina or not Montevina?

Following the announcement of the new iMacs, and their rather surprising specification, the websites are speculating on what is really inside of those new iMacs. Whilesome websites seems to have mixed up plateform code name with CPU generation, the hardware sitting in the new iMac is for sure exotic.
According to several websites, CPUs are a "special" model of the current 45-nm Penryn processor, but not officially available from Intel catalog. Those special CPUs feature clock speed ranging from 2.4 GHz over 2.66 and 2.8 GHz all the way to the 3.06 GHz CPU with 6 MB L2 cache and a 1066 MHz FSB.
So, the second point is the chipset, as the current Santa Rosa is reported to provide FSB topping at 800 MHz, and here Apple claims to have 1066 MHz FSB processors powering the new iMac. So, either it is indeed 1066 MHz FSB capable CPU on a 800MHz Santa Rosa FSB, or the new iMacs feature a overclocked version of the Santa Rosa to bring support for 1066 MHz FSB.
If the figures for the CPU seems clear, and is not so much a surprise as Montevina was compatible with Penryn CPUs, the current chipset sitting in the new iMacs remain an opened question. It really looked like the Montevina based on the 1066 MHz support, however, Apple being using CPUs not officially available from Intel, Cupertino might also have had access to an overclocked Santa Rosa, allowing the company to offer an upgrade, while waiting for the next one which will be then based on Montevina.
It would be nice for us as well as the end users that Cupertino starts providing full details about Intel CPUs and chipsets being used in our Macs.
[update]:
Apple released a TechNote dedicated to the new iMac, there is unfortunately not enough information to clearly identify the chipset being used, either an overclocked Santa Rosa Refresh, or the Montevina.
Direct link: http://developer.apple.com/documentation/HardwareDrivers/Conceptual/iMac_0408/Articles/ProductDeveloperNote.html#//apple_ref/doc/uid/TP90004831