Why would Apple put the low end 2.5Ghz right next to the high end 2.6Ghz? It'd make more sense to make 2.4Ghz the new low end and keep the 2.6Ghz. They won't use the core 2 extreme because it uses some ridiculous amount of power (45W instead of 35W).
I would have to agree that I don't think the MBP is coming out this month. The SR refresh isn't a big enough change for the trouble really. I'll think they'll wait for Montevina, which will allow them to redesign the thing from the ground up if they so desire. Also, the new Nvidia mobile graphics chips will be out, so the ENTIRE machine will have new hardware.
I'd also assume that SSD will make an appearance, hopefully it will be more affordable. 128GB SSD's are $3000, but 64GB is $1000 now (in the MBA anyway.......), and should drop at least a little soon, when more laptops start to support it.
Based on those predictions, I think it would also be safe to say that without the hard drive, a smaller logic board, more efficient processor, and LCD displays all around, this will be the most power-efficient Mac ever, and have a significantly longer battery life.