I think it is in Casey's best interest to come clean if she wants to save herself from the death penalty. Baez is probably going to hold out and wait for the official charges and then say, "we'll take you to the body if you reduce the charges on my client to involuntary manslaughter" The states attorney will most likely not deal this late in the game, body or not. They have an overwhelming amount of circumstantial evidence to put her away for life without parole.
Remember the day Westerfield was charged with Danielle Van Dam's murder? Feldman (attorney) met with the DA to bargain, and the DA told him to pound sand!!! Coincidently......Danielle's little body was found on that same day.
Caylee is now Casey's bargaining chip. :behindbar