I know this is bit out of the topic, but a practical and stable solution will be MS .Net Compact Framework + MS SQL Server + Web Service. At least that's what I have done when a offline mobile solution was needed. And it works.
I checked Google Gears before i started to work on it, unfortunately, it has not yet implemented that. Hope in the near future, the synchronization framework between SQLite and somewhat databases (MS SQL, MySQL, etc..) will come out. Regards,
