Because 50 MP wasn't enough, Canon just announced the development of a 120 MP EOS camera body.
So, my 5DIII has a sensor that is 5760 x 3840 and a 6.25 um pixel pitch. The 5Ds(r) has a sensor 8688 x 5792 and a 4.14 um pixel pitch. The 120 MP (assuming FF sensor) would be 13,416 x 8944 with a 2.68 pixel pitch. Maintaining 300 ppi, the 5DIII could do 19.2 x 12.8 inch print, the 5Ds (R) 29 x 19.3 inch, and the new 120 MP sensor 44.7 x 29.8 inch print.
Relating this to my 5DIII, the 5Ds(r) has 1.51x potential more resolving power (tests showed 1.2-1.4), and the 120 MP sensor camera would be 2.3x more resolving power (of course, no real world data on actual improvement).
It is a crazy number of MP. The file sizes would be huge. Yet......cool.