It already is, and as of this writing is is the #1 bestselling music video.
Any group of any particular Game Development Companies or Game Development Teams.
The Halo series and Super Mario 64.
call of duty black ops
The bestselling video game of all time is Tetris 1984 with 143 million copies sold followed closely by Wii Sports, and Minecraft in that order.
There are quite a number of various companies who worked on the development of the MMORPG Stargate Worlds. The two that announced that they had begun on its development wasCME and MGM.
Tom Clancy is a well-known author who created a series of novels that have been adapted into video games. However, he did not personally develop the video games himself, as game development is typically handled by game development studios and companies.
There is quite a list on: http://www.igda.org/colorado/list-colorado-game-development-companies
There is no top person as there are many different jobs to design a video game. There are major companies though.
EA (Electronic Arts), Activision, Eidos Interactive, GameLoft, Konami.....
There are many companies that might be wiling to hire young games testers since they are their prime consumers. For example, the major video game companies such as EA games.
Halo, Mario, Zelda, Grand Theft Auto, Ratchet and Clank, Jak and Daxter.