I am in Tucson and was one of many bidders at the auction and noticed that there were folks working on that Hummer both Fri and Sat but have no idea what actually happened to it to cause the fire. Great fundraising effort though!
On a separate note the gentleman that won the SuperSnake for $5 million also purchased "The Last 67' Stingray" and a few other cars totaling about $8-10 million. His name is Ron Pratte and he's in construction (framing and concrete) in Phoenix and he sold part of his company to Pulte Homes in order to pursue his car hobby a couple of years back. He has quite an extensive collection and gives a great deal to charity.
A brief overview of Mr. Prattes success
http://www.buildingonline.com/news/viewnews.pl?id=2805