This was tried years back. I forget the name of the case, but it was in
idaho.
It was the same "fat boy defense". The deal was that lethal injection was shiny and new, and inmates sentenced to death got to choose between the old method (that they were sentenced under) and the new. In Idaho, old school was hanging. The defendant argued that choosing his own method would mean that he acquieced to his own muder. Therefore he would be hanged. But hanging could result in decapitaion because of his extreme weight, and therefore it was cruel and unusual. The appeals court said "No, but thanks for playing".
I think a .40 to the back of the head would alleviate his concerns.
FQ13 who hopes that they invited Black Bart's horse to the hanging. It would only have been justice for the poor animal.
PS How do we allow someone on death row to reach 480 pounds? Its not like they're running out to the quickie mart for twinkies?