"The other part of my problem with Canon, and that has nothing to do with future price of 6D is why the control layout between different levels of cameras is so different. Somebody who starts with a xxxD and moves to xxD or xD will have to relearn muscle memory for controlling the camera. If you have to relearn all the layout then what is keeping you with a brand. I don't know if that is the same with other manufactures, but I think that is so stupid."
I typically carry the 6D with the 300 2.8 X2 and having one hand on the lens and being able to view shots using just the right hand is great. My 40D requires both hands on the camera body and is not nearly as convenient. The problem I have is that my finger sometimes is challenged with the select button within the L R U D selectors so when deleting a picture I sometimes end up forward or back. With some tweaking the 6D layout is superior IMHO.
Put a better AF as mentioned and a bit higher frame rate and I wouldn't even consider a crop second camera.
6D and me.