Houses of the Future

Available now in the UK, costs a couple of dollars to run, is based on a modular system and made from glass and steel.
Can be added to as

Have a watch at: http://news.bbc.co.uk/2/hi/business/8704307.stm

Similar projects in Aus:

http://www.modscape.com.au/
http://www.prebuilt.com.au/

Very interesting design: http://www.domeshells.com.au/