Provide replication for off-line clients

Some commercial databases, such as Microsoft SQL Server, has the possibility to setup a replica for off-line clients.
Although we're facing an on-line world, there are some intermittent connected devices such as laptops, netbooks and PDAs. A database feature that offer replication for off-line users would allow those devices to access applications and continue working on data, while merging while back on line.

Although the code of replication might be inside MySQL/Maria DB, the major issue is handling replication conflicts: might be as simple as warning the user that the particular row has not been replicated for conflicts. A GUI or a set of API should be provided to setup and access the replica.