For the 4 bodies, I'd go with a 70D, budget FF, and how about TWO mirrorless bodies? A lower model and a mid range model? The 650D showed us something a bit different, and I can see the new toys making their move into the 70D at least and it would be a good fit for mirrorless.
traveller, a budget full frame just wont kill the 7D. If you need crop, you need crop. They are too different. Even today, if you offered me a choice of 7D or 5D2 to use day to day, it would be the 7D no question. Use the right tool for the job. Full frame isn't the only tool.