For a teleconference room, check the usual suspects Polycom, Cisco, Vidyo, etc. You usually can have a room wired for that specifically or buy a cart and move it everywhere. Maybe have a decent room with many microphones, two HD cameras and a touchscreen interface. And a cart with less capabilities. That's what we have and it works well when the main room is occupied, we just put the cart in the middle of somewhere and people gather around.
I'd spent a good time making sure the softphone client that goes along with that solution plays well with your target systems. Sometimes the quality between Linux, OSX and Windows clients can vary a lot.