How does it perform with many people at once (think of a trade show booth hall - if there were 300+ people running an app would it be practical to use this to direct users to a 3x4m booth amongst a hundred or two such booths)?
See this GIF: http://i58.tinypic.com/33nyrgo.gif It's a 30m x 15m space (half of your space) and we used 12 beacons. You can use less if you want "corner / room" level accuracy.
Because beacons broadcast signals all around any number of devices can access their signals and there is no limit in number of people with mobile app that uses our SDK. If you put beacons high enough the signal absorption should be minimal, but we haven't tested with high density crowd yet.
That gives me some ideas.