It would be very cool. Mark Millar has teased about Kick Ass 2 since the first movie!

Yes indeed Lady T, I cannot see the spirit of Big Daddy leaving the earth without a fight , especially considering the circumstances of his demise and how absolutely dedicated he is to hit Girl ...and their cause! not just this, what a cool dimension to a comic and a film, it opens things out... How open Mark Millar would be to the supernatural entering his vision who knows...especially as Kick Ass was a kind of contemporary real world deconstruction of the superhero fantasy! Needless to say , he did not respond when i mentioned this suggestion to him on twitter, but who knows he may be scribbling it in as we speak!!