Last year at the DTS run a guy showed up in a nice Avalanche buggy running rockwells and 49" iroks. He was denied and ripped a foot sized hole in his sidewall. It was pretty fun to watch, but sucks to replace that tire. A few other guys tried it as well with noone making it all the way up.
They are doing another DTS run this year on the weekend of May 4th-6th; which unfortunately is the same weekend as my daughter's birthday party. It should be a good time though.