AD Import, Multiple domains

We have multiple domains in our forest and due to mergers and acquisitions we have multiple users with the same username (different domains of course). The domains are months away from consolidation so we are using the department feature to distinguish the different domains, but we are having a problem importing the users.

The problem is that the import tool only appears to use the samAccountName to verify whether or not the user is new or exists. As a result, existing users are being overwritten.

1. There does not appear to be a log of who was imported/overwritten. Is there one I am missing?

2. Is there a way to have the system refer to samAccountName and Department to determine duplication rather then just samAccountName?

3. Request feature: Confirm duplication/overwrite. This would be great if this was an option during import.