They will make a Dual Core based on the Nehalem micro architecture but it will not be an actual Core i7. They will have the same architecture. You are correct...Core i7 is specific to quads. Many people think the new processors will be the Core i5. People claim to have already tested them and showing benchmarks...I could make those shots in Adobe Photoshop in about 15 minutes...I don't believe any of them yet. Here is about all Intel has said on the new series.
http://www.intel.com/pressroom/archive/releases/20081209corp.htm
As far as I could ever find...Intel has not really made an official announcement as to what it really is. Nothing really is fact at this point that I could find. I copied this from an article and was going to paste it in last night in my original post. It was from tech news magazine in the UK. Who even knows how true this is?
"Fortunately, Intel's CPU roadmap also includes lower-priced alternatives to the Core i7, codenamed Lynnfield and Havendale. The Lynnfield and Havendale CPU models are to follow Intel's current Core i7 processors, codenamed Bloomfield. These new processors are slated to launch sometime in Q4 2009, and will be designed for the mainstream market, coming with a price tag of under $200. Despite the fact that we are still far from an official release, it appears that one of the Lynnfield model processors has already been put through its paces."
If they do perform as well as they are expected to for a price launch under $200...it might become popular quick.