Don't know how true it is but I've heard from 4 people that claim they were there that during a random practice back in 2009 chris herd did a standing triple full and landed it for the first time but no one recorded because he didn't expect to land it. Again don't quote me on this but I've heard this from 4 different people.
If you count triple full as a backflip with 3 twist it's true that it has nothing to do, but since a cart triple counts as a triple full then I can clearly count the triple full of shosei