Yeah, I can't say that they are completely wrong but the rumor sights are never exact so I am gong to keep my hopes up for 3Ghz. I would hate to see Apple gives a cheezy 2.7Ghz up from the 2.5 dualie. On the other Intel does these modest increments as well. Every new Intel processor has gotten a 200Mhz upgrade from the previous.
If Apple doesn't deliver a much higher clock speed model then it better be a much more efficient processor if they want to keep sales going and a much better graphics card.