Why can't you run a SQL profiler replay trace, capture it for a brief period of time and run the replay in a test environment?
If you're concerned about the Profiler overhead you can script it out as a server side trace.
Also, go grab a copy of Itzak Ben-Gan's book "Inside Microsoft SQL Server 2005: T-SQL Querying". Chapter 3 actually has a pretty Chuck T. Awesome way for capturing and performance tuning queries based on wait times.
In fact, you can go grab the sample code here, but don't tell anyone... its our little secret.