So far, the Data Port Sync preview has already some synchronization capabilities. It will only work safely with one PDA and still has no collision handling code. When the same row is updated on both ends the PDA prevails, but this will change soon as collision-handling policies become available.
The day's work was spent on calculating INSERT order for tables (reverse of DELETE) so that database structure and constraints are not violated. Also, work is under way to support multiple PDAs synchronizing against the same database.
Hope that by the end of the week I will have more to write about.