[Bex]

I think it's actually reasonable to expect that Ledger could be in the next film - if he was intended to appear in it as a cameo, then that would have been shot before his death, during the filming of TDK (to save it on one contract, and to help continuity). I think they did a similar thing with Scarecrow's cameo (you know, filming it during the previous film, in this case, Begins).

If Ledger has a cameo, it would be nice to see him briefly in Arkham Asylum, which would bring a bit of closure, as well as being a good introduction for The Riddler.

Well... I doubt it'll happen. The 'We're destined to do this forever' sort of hinted that they were planning for Ledger to be The Joker again. Bollocks. I want Ledger back *cries*