Judging by the specs, the new body should fall between the $3399 list of the 5D3 and the $1899 of the 6D. I'm guessing a $2599 list. It won't be below the $1899 of the 6D because the 70D is at $1199 and Canon doesn't want to cannibalize those sales. If they use the 5D3/6D ratio, then a new APS-C body would be $2149 which would be great and shouldn't affect 6D sales.
Somewhere between $2149 and $2599 is doable unless the used 1D Mark IV falls below $2000
Somewhere between $2149 and $2599 is doable unless the used 1D Mark IV falls below $2000