I watched this happen at the Hunter Airshow at maitland last year. He was coming in doing what these STOL blokes do, on the backside of the curve with power with very little margin above the stall, trying to land as short as possible.
It was a fairly windy day with some gusts around. I am no accident investigator so this is only speculation, but it seemed to me not enough margin above the stall, hit a gust, wing dropped and down she came. Regardless of the cause of the stall, a stall it was. Unforgiving with power on at that altitude.
It was a fairly "soft" crash and a pretty good advertisement for the aircraft I think. Those big shock absorber struts certainly absorbed the impact well. The speed he was flying certainly helped with minimum energy to dissapte. Bugger all forward velocity.
As an aside, this aircraft will crap all over a Supercub in a STOL contest (this landing example notwithstanding!). Great little aircraft. It is back flying again.
Cheers
CB