Ideal Migration has significant capabilities for domain migration. Its characteristics (from product page):

• Runs under MMC 1.1 or higher
• NT 3.51/4.00 domain consolidation
• Migration from Windows NT domains to Windows 2000
• Migration from Windows 2000 to Windows NT domains
• Windows 2000 domain consolidation
• Off-line and on-line migration
• ******** Migrate user account passwords from Windows NT to Windows NT / 2000 ************
  A particularly important feature for a seamless migration
• SIDHistory management
• Migrate Terminal Server properties
• Manage multiple source computers/domains
• Manage multiple destination computers/domains
• Record object properties into CSV files
• Three modes : Add, Modify, or Add and Modify
• Migration wizard
• Migration by category
• Selected objects migration on one or several computers/domains
• Consolidated/Migrated objects
  • Computer accounts,
  • user groups,
  • user accounts,
  • group memberships,
  • organizational units,
  • shared folders,
  • printers ports,
  • printers,
  • file and folder securities

Aelita Domain Migration Wizard seems to have particular stengths in domain consolidation (from product page):

• Migrate Windows NT 4.0 domain directory into Windows 2000 Active Directory domains and organizational units
• Migrate Novell NetWare resource servers to Windows 2000
• Reconfigure and process the Exchange directory at the same time with accounts migration
• Maintain resource access and auditing settings by updating object security descriptors throughout the network to reflect any number of account migrations at once
• Perform zero downtime server consolidation/reconfiguration by moving and synchronizing multiple distributed storage locations

Altris has release AXMT, the Altris Migration Toolkit, which is a soft bundle of products and technologies designed to assist your migration to Windows 2000 or Windows XP. The Migration Toolkit provides you with a complete pre-migration inventory assessment, PC cloning/network configuration, software installation, personality restoration, and post-migration status report in a single tool. It is the only complete migration solution. Focus is workstation migration.

It is difficult to know how to evaluate such complex utilities. If you have had hands on experience with this utility or a similar product, .

well written. it is essential. or at least very valuable.