see, you guys keep thinking a fast FF body will make the 5Dii obsolete... But canon makes a 1Diii and 1DsIII. They're not a whole lot different than what we're saying here, yet canon gladly carries both in the line and gets a very nice premium for the 1Ds. people also thought there was NO WAY canon would dump 21mp in the 5Dii as it would "kill 1DsIII sales!" and look what happened there.
and as I keep saying, if the sensor cost goes down even though the wafer space is the same with a 12mp sensor (or 16), and they use the same memory but just bump the FPS they could be SAVING money with the 7D which would mean they wouldn't care if it killed the 5Dii all together. Having something FF and ~12mp and fast to compete with the D700 is a lot better than losing customers to Nikon. Would you rather steal your own money, or let your competition steal it?
The difference between the 1ds3 and 5d2 is that the 1ds is FF and has wicked fast AF and more AF points. It is a lot more camera then the 5d2, and lets not forget it's a true pro body.
If the 7d was truly a FF sensor with fast AF, more FPS, and more AF points, and for a cheaper price then the 5d2; then why would people even look at the 5d2. Even if the MP's were dropped to 12-15, people would still overlook the 5d2. The 5d2 requires a big upgrade for most shooters on this forum, unless they want to shoot in sRAW. Who knows how many people purchased the 5d2 that are not on any particular forum, but Canon is not going to want to harm the 5d2 with a cheaper FF camera with more speed.
Look how long it took Canon to actively replace the 5d classic.