We are migrating our SharePoint farm and users (about 4,000) from one domain to another. During the transition, it is a requirement that the users have access to their sites from either their old, DomainA accounts or their new DomainB accounts. If we didn't have that requriement, I'd just do a STSADM MIGRATEUSER command for each user. But doing so will remove their DomainA permissions.
How do I do a farm-wide copy of a users permissions from an old to a new acount, at the site, list and file level, and there SharePoint group memberships?