I have seen lots of these popping up on the web, especially some of the facebook posts of the teams in the states. Harry Soo has actually starting showing people how to do these in his BBQ 101 classes.
Never had a go at it myself, I'm guessing its a time consuming prep.
I'd cook some for Sica (my partner) but she'd instantly jump to the conclusion that there had been an accident involving her pet tortoise and that I'd tried to cover my tracks with a bit of sneaky BBQ misdirection.