Tim Clark interview:
http://www.theaustralian.news.com.au...-23349,00.html
"If you look at our Airbus A340-500 economy seats -- the weight of the seat is 29.5kg, the weight of the seat downstairs in the A380 fully dressed is 18.5kg," he says. "We've pulled back 11kg on the 340-500. The target is to go down to 14.5kg, fully dressed, on the next-generation seats."
I think that's a good effort; you might wonder: what's next? Here's my idea of a super lightweight seat:
Inflatable seats :P
Or, you might imagine the whole of the middle section (4 seats) replaced by a beans bag couch.