Now that Justice League Unlimited is cancelled, do you think Cartoon Network will create a follow up series?

Answer 1

Who said it was canceled? They only ended Season Two. But with the production time necessary for animated programs, Season Three will not be on before late fall 2006 at the earliest.
But if it is canceled, they should go back to episodes featuring actual comic book JLAers, considering most of the extra characters are actually members of the Justice SOCIETY of America.