Streaming live video from a camera to a display using two arduino UNOs
Possible yes - practical very difficult. 
In theory you can send video, but the uno has very little processing power which means that the resolution and framerate you will achieve is probably unsatisfying. I'm not currently aware of any libraries supporting this, so if you did go for this solution you will have to do a lot of programming your self.
I would recommend you to use a raspberry pi instead, or similar. This has the advantage of you being able to use a lot of ready made streaming library. In the end this will take you a lot further much quicker. 

Check this out to get inspired: http://www.instructables.com/id/Raspberry-Pi-Video-Streaming/