I won't even discuss the copyright implications of your question, as you must be doing this in a business (like hotel) environment.
You are going to have a very difficult time using wireless to stream that much bandwidth without using commercial grade (i.e. very expensive) equipment. A gigabit wired connection to a high quality gigabit router would be the better approach. Another issue will be using a disk array that is fast enough to serve so many clients with video bandwidth, which is a lot of data.
What kind of video quality do you envision, HD? And as leo2kp says, if you will do simultaneous transfers of different movies you are talking about a not only a fast read from the disk array, but also the bottleneck at the interface of the NAS to the network.