Well...Although I'm on my annual 30 days leave,I'm located in Rio,very close to Sao paulo,and in contact with a few coleagues I've heard nothing of this rumor,and if you know SBGR you would say it isn't very likely...Both taxiways that run parallel to the runways are too narrow and too bumpy for an A340 to land and without being subjected to some damage...I'm pretty confident I would've heard something..