You could always try our local Aussie airline
http://www.qantas.com.au/Not sure if baggage rules are still the same and how they compare price wise but last time I flew with them you were allowed 23kg check in and 2 x 7 kgs bags carry on (not many people take advantage of the carry on rules), I managed to squeeze two lightweight 3 strut kites (6 and 9mtr) into one small kitebag and carried it on along with another bag with clothes, camera etc.
The bags weighed approx 7 kg each and were just under the allowed dimensions, I was questioned about the size and weight but when I assured them they were under the requirements they let me though without checking.
Board, 12 mtr kite, harness, bar and lines, wetsuit, towel all fitted in the check on board bag so no excess at all.