Easy Client transition from Win 2000 domain to win 2008 domain

Is there a registry hack, microsoft tool or some other easy way to transition user PCs from the single name Win2000 domain (DOMAINXYZ) to the FQDN required by Win2008 (DomainXYZ.xyz.com). All PCs are XP Pro. Unfortunately, in the test, to move the user requires a “new” profile.

The “quickest” method is to a)backup the profile using the “settings and migration wizard”, changing the PC to a “workgroup”, then hooking into the parallel network with the 2008 server, creating a “new” profile, and restoring the backed up data using the data an Settings and Migration Wizard. This is a small company with about 25 PCs.