Why on earth would you need 30+ MP for a studio shoot? So you can print stuff on the sides of buildings?
As a matter of fact yes. Go to Macfly's website and you'll see that he does shoot images (movie promos, mainly) that do indeed go on the sides of buildings.
Seriously folks, it's bad enough to flame people, but flaming people without having a clue what their history and needs are is just ignorant.
There are a lot of reasons for solid use of a 30+MP camera... As everyone I'm sure has read from me before, I'm a huge proponent for more MP, but with that being said, I also understand there's a place for every camera and every use... As i've mentioned before, in film days, a 35mm camera rarely was printed at anything bigger than 8x10... even at 8x10, with good old tri-x film (ISO 400), you could see some grain. Sometimes you would be daring and ask your lab (or push it in the darkroom) and pump out 11x14's, but you knew you were going to lose quality... Professional photographers knew and had in their back pocket MF cameras or even large format cameras for bigger prints...
Now adays with cameras we can pump out 16x20 practically without any interpolation with the 5d/7d printing at 300dpi. I have shot murals with my 7D that were put on tradeshow booths (20 feet wide) however they were still lifes and I was able to shoot the large scene in sections and stitch together to build a native file without any interpolation. Larger MP's would mean that I could do that with less stitching and make things essentially quicker, better, higher profit margin, however I hope that we keep in mind the limitations of the 35mm format and if you have the rare need for super large images, not to expect a 35mm to pull that off but instead look at MF with digital backs or LF with digital/scanning backs instead.