I personally think the tournament thing is bogus, if Piccolo is such a bad guy, why fight him in a tournament where he can hurt other people when they could gang up on him and beat him down?
I've thought of another thing also, is James Marsters playing Piccolo or voicing him? Because they could surely make him CG like Yoda in Star Wars, does that mean Piccolo, the demon master will look like a human, like he's hiding in disguise or something? Will he only turn "green" at the end, when he's like being pushed to the limit by Goku?
Also links to pictures of the Mexico City set:
HoyCinema: Movieland - ¡Exclusiva! Primeras imagenes de Dragon Ball y set que se utilizara en Durango y Emmy Rossum se une al reparto