How about looking into this. Making it so really huge renders can be broken up say into 4 smaller renders then put back together in a different program. Like say I want to render a print size 2000 X 2000, to be able to render it in 4 or more pieces say 1000 X 1000. All it would need is better camera control. This could be easily accomplished if you could just set the render selected to exact numbers and be able to move the box around a bit. No#1 being able to scroll a bigger than the desktop size instead of the present you have to render it to disk.