I disagree on almost every point, but hey, that's why it is called a personal opinion.
1D: I don't see them being merged. They are professional tools, not intended to the same people. And as every tool, they are made for a special job. So stop one of them and you make a lot of pro users very unhappy. Furthermore, if they are really merging, why the price would be closer to the cheaper model? If it become a double side knife, it would probably cost more than a previous single side one.
5D3: I expect it for Photokina 2012. No emergency to release it earlier. Still great sells, and no opponents.
3D: a cheaper FF camera is highly possible. We have a huge wolrd crisis, offering a cheaper option is always welcome and a smart move from companies. But if so, it would just be a cheap made 5DII: same sensor, same AF, plastic body. Maybe EVF?
7DII: after 1Ds, that is probably the most urgent body to replace! Others company released (Sony a77) or will release soon (Pentax, Nikon) new
cameras with higher specs. I insist very much on the word "new", because it is usually the most important word for people buying a camera (we see here every day people telling they won't buy a 5DII because it is "old" while they is no new competitor, what would happen if there were a recent competitor?
60D: will be replaced in 6 months, as usually (every 18 months). Maybe it can be pushed until next Photokina (Sept.)
600D: to not replace it next year means to kill the sells and incomes. These entry bodies need to be replaced frequently (cf my "new" comment earlier). So it will be replaced next January/February as usually. Then, which sensor? Still the same? For the 3rd time? I don't think so. That's why it will push Canon to replace the higher model 7D earlier too.