Just noticed a new KB article describing the RML utilities for SQL Server 2000 and 2005 http://support.microsoft.com/kb/944837 which supersedes http://support.microsoft.com/kb/887057. I haven't had a chance to play with this tool yet but it looks pretty good. I particularly like this feature:
"After you capture a trace for an instance of SQL Server, you can use the RML Utilities for SQL Server to replay the trace file against another instance of SQL Server. If you also capture the trace during the replay, you can use the RML Utilities for SQL Server to compare the new trace file to the original trace file. You can use this technique to test how SQL Server behaves after you apply changes"