OK, that sounds more appealing. I'm sorting out all inputs and so far my concept design would be.
Surface RT's for the tablet. Since they are pretty darn cheap for a windows touch tablet. And I'm not sure how to go about with an android device.
A PC acting as a media server and a separate NAS for the lecturer files, which would be mostly power point one would think.
The PC will attach to a switch which also connects to the various APs that would be configured as a single point.
2 HD IP cams would be attached to the switch and the PC will act as an NVR that would record and also live stream the video feed. The feed would be captured by the tablets via IP address using IE.
Or I'll look around for a dedicated streaming software. I'm not sure yet.