This entire system is built on custom made mini-ITX boxes running Gentoo Linux adopted for embedded environment by me with the majority of the software written by me.
Most of the boxes have no OS or internal storage and boot from the network wirelessly or wired. They then mount their roots and filesystems via NFS.
The Audio/Video units can read their data via NFS or via custom network protocolI call NVAS (networked Video Audio System) developed by me.
Wireless Audio System in Grand Hall (note I started with an iPod, before moving to full mini-itx system)
Wireless Audio/Video in Theater
Wired Surveillence DVR
Main Internet Gateway
Wireless Access Point
Outdoor PTZ camera (27x optical zoom)