Razerwire has had problems with RaceDeck coping with his heavy bus but it's easily capable of supporting a normal car's weight.
Don't know about the cost in Aus, but have a read here:
http://www.racedeck.com/acc.html
I've seen some really nice RaceDeck floors but for mine I'd still be inclined to go the etch/seal route, being sure to give plenty of time between the various processing stages and again before use.