10 years ago a geek mate of mine was bored and asked me to come up witha 'project'. If it interested him he would do it.

I said I wanted him to set his house so he knows exactly how many people are in each room at any time for alarm/security purposes, to link doorbell to SMS and have webcam and VOIP( although not called that back then!) so he could see and speak to whoever rang that bell. He extended it to include proximity sensor locks on all external doors ( imagine walking up to your front door and it unlocks, walk away and its locked solid )and even using teh prox sensors to know 'who' was in each room so it could adjust central heating and lighting to personal preferences.

This was 10 years ago!!! and it worked a treat!

All I can offer to you is think network, network, network... you can send audio, video, and any other data you want over ethernet.. what you do with it at the other end is up to you.

I method and design pattern you SHOULD read up on is SOA ( Service oriented archicteture )

Its how thw world is looking at integrating systems on many different systems. it uses a messaging based system and Enterprise 'bus' to send data around and between disparate systems. your bespoke sysytem only needs an 'interface/API' for ANY other system to talk and interact with it.

happy to expand if any/all of teh above is goobledy gook!