The main reason for another identical body, as well as the ones stated above is all your lenses will be the same. You wouldn't need to think this lens would be 50mm on this and 80mm on that (7D).
At minimum, get another FF, going for a crop creates havoc when shooting. If you have a 24-70 on the FF, to get 70-200 covered on the other body (when shooting with 2 bodies) you will need the EF-S lens. Pain in the bum IMO, that lens then become useless on the 5D. You end up restricting yourself with your own gear. You want all your lenses to work on all the bodies.
That really depends whether you value the extra reach of the 70-200 on a crop. The 5dmkII has plenty of resolution to crop from 70 to make up for the small gap (70 to 112mm equivalent)
Cropped to make it like 70mm yes, but it is not its true field of vision.
It is a pain in the arse shooting 2 bodies in different crop factor, speaking from experience here.
Owner of 2 x FF and 1 cropped body.
....People are obesses with "reach"! Just use your feet. If one wants more reach he simply buy a single longer lens,....
.....Please don't pick and choose!
People are obesses with "reach"! Just use your feet. If one wants more reach he simply buy a single longer lens