Hi Davros,
Why note take a look at the Crestron Audio and Video distribution system. There are upto 16 YUV inputs for video and audio. The system is modular and will cover up to 32 outputs. These signals can be sent via CAT-5 for video and audio or line level to amps on the audio.
You can also send local audio and video souces back around the system from the rooms that the signal goes to.
The Crestron will then also control all of the sources that you have going into the system as well as the local display sources. If you use the 10" WiFi touch panel you can use the Remote Desk top to view the menu from the frolm the media server and receive feed back from devices in the rooms.
The only thing that limits you is the budget. Have a look at
www.crestron.com and look at products CNX-BIPAD8A, CNX-PVID8X3, CNX-RMCLV and TPMC-10 in the products section of the website.
Good Luck
Blaze