I'm flying on Etihad from Brisbane to Singapore at the end of next week, and have been invited by Etihad to bid for an upgrade fom economy to business class.

I'm flying on Etihad from Brisbane to Singapore at the end of next week, and have been invited by Etihad to bid for an upgrade fom economy to business class. Loading is light in business at the moment (> 9 seats still available out of 22). Has anyone here successfully booked such an upgrade and, if so, at what rice point?

Successfully used this system to upgrade my wife from MEL-AUH and return. Similar circumstances, there were >9 seats available and economy was pretty quiet (according to expert flyer), so I was doubtful they would upgrade. We 'bid' the lowest price per sector (which was about $650 i think). We got an email 48 hours before telling us it had been accepted. So yes, it works well. 

Also, a colleauge of mine recieved the same email offer - he bid, but also called Etihad directly, who proceeded to upgrade him on the spot for less than he had bid (this was from business to first). This didn't work for me (I was quoted the difference from economy to the cheapest business fare), but you could try it too if you want!