Thanks for the quick answer.

How would you describe the differences in IQ between the 1ds3 and the 5d3?
These are the Canon lenses that I have:
TSE 17/4 L
TSE 90/2.8
135/2 L
1.4x TC
17-40/4 L
85/1.8
50/1.4
...and they are the only reason for not getting a Nikon D800.

OR... I could keep my 1Ds MkII for use with my present Canon lenses,
and for the price of 5D MkIII body I could get a D800 + Nikkor 85mm lens for studio portrait work,
...AND buy a tilt shift adapter,
that will allow me to use my old Hasselblad Zeiss CF lenses on the Nikon.
http://www.mirex-adapter.de/tilt_shift_adapter.htmI already have Zeiss CF 50mm FLE, CF 80mm and CF 150mm lenses
and they can make a great Nikon tilt shift setup.