I've been watching with interest the old County Court building in William Street as it nears completion. Nobody I asked knew what was going to happen to it, though it looked suspiciously similar to its previous incarnation, and very court-like.
The Government released a media release earlier this week, announcing this will be the William Cooper Justice Centre, providing extra court space for the Supreme and Children's Courts and other courts as required, and other hearings such as Royal Commissions. I guess that trials such as the high-security ones held in the County Court will also be held there.
You can read a little bit about who William Cooper was in this media release, and also on Wikipedia.