Honestly I don't think they had planned on having him in another movie. I heard Nolan wanted to make a Trilogy. Since Harvey Dent is in this one, I suspect he'll be the final bad guy in the last one as Two-Face.
CBS 2 has reported that along with the prescription drugs that were found in the apartment, police also recovered a $20 bill with narcotic residue on it and several drug packets containing an unknown substance.
http://community.livejournal.com/ohnotheydidnt/19639284.html?#cutid1
TMZ confirmed the presence of medications Xanax and Valium in the apartment in addition to the Ambien sleeping pills and several medications prescribed in Europe reported earlier.
http://community.livejournal.com/ohnotheydidnt/19646403.html
Apparently, Ambien is a controversial med in Australia, where it's called Stilnox, and has caused hundreds to have bizarre and potentially dangerous reactions to the drug including, but not limited to, walking, crashing cars, having sex and falling from balconies... rage reactions, worsened insomnia, confusion, agitation, hallucinations and other forms of unwanted behaviour. One patient gained 23 kilograms over seven months after unknowingly eating from the refrigerator while asleep. Another patient woke up with a paintbrush in her hand after painting the front door.
http://community.livejournal.com/ohnotheydidnt/19631657.html
http://news.smh.com.au/ledgers-sleeping-pill-controversial/20080123-1nou.html
Whether or not Heath ingested all or any of these drugs is still speculation as the results from the medical examiner's autopsy came back inconclusive, and further test results will take about a week.
Crew members on Heath's latest venture, The Imaginarium of Doctor Parnassus were let go yesterday according to Us Magazine. The movie, co-starring singer Tom Waits, had started filming in December. With the passing of the actor, production has shut down and they're trying to figure out what to do with the little footage they have.
http://community.livejournal.com/ohnotheydidnt/19639607.html
edit//Sources from the NYPD tell TMZ that nearly full bottles of anti-anxiety medications Xanax, Valium, and Ativan were found in the apartment with sleep medication Lunesta and sedative Restoril. No mention of Ambien as stated earlier. All drugs were prescribed to Ledger.
http://community.livejournal.com/ohnotheydidnt/19662365.html?page=3#comments