Well the problem with the DigiTimes report is that those chips aren't on the Intel roadmap. The Yorkfield chips flip the bill, but they are desktop units. Would they work in a iMac/Mac Mini? They are Quads.
As for notebooks, there are Penryn XE's. They would be 45nm and could work. But we're still in 2-core territory with those. Penryn QC might be a contender.
Well I know that Dell is using the Intel Core 2 Quad Q8200 processors in their XPS ONE systems (http://www.dell.com/content/products/productdetails.aspx/xpsdt_one?c=us&cs=19&l=en&s=dhs&redirect=1)
I'm not an expert on chipsets so I have no idea what kind of chip that is and whether it would work in an iMac.
I know from a dimensions standpoint, the XPS is 18.0"H x 26.8W x 7.9"D and the iMac is: 20.5"H x 22.4"W x 8.1"D. (this is for the 24" versions).
-Kevin