It is possible to do a migration in 5.0 from Production to Sandbox, arrange islands how you want them to be arranged, and then migrate just the arrangement information back to the Production portal. This is the SQL script to do it.
Note: TargetDB is the database getting the information. SourceDB is the database that has the information to copy.
UPDATE [TargetDB].[dbo].[PWPageIslands] SET
[Left] = [x].[Left],
[Top] = [x].[Top],
[Width] = [x].[Width],
[Height] = [x].[Height],
[ZIndex] = [x].[ZIndex],
[PrimaryColor] = [x].[PrimaryColor]
FROM [SourceDB].[dbo].[PWPageIslands] x
WHERE [TargetDB].[dbo].[PWPageIslands].IslandInstanceID = [x].IslandInstanceID