Perhaps the best way to revise your case study on US production studio is to compare it with a British one. Here are two case studies of UK Film Studios which could be compared with Hollywood production companies. The main issues of production, distribution and exhibition can be compared and contrasted in a number of ways.
The following link is a brief case study for Working Title Films.
The next link is a more detailed case study for Channel Four's Film Four.
This link is to a very useful three part article on the production issues behind Channel Four's Film Four and their place in the British Film Industry.
Consider cross-media ownership, particularly as Working Title Films is mostly owned by NBC-Universal! What are the implications for this "British" company if the main source of its ownership and finance is American? Working Title make American films as well as British ones. A fact sheet will follow based on the mini case study above.