Test Accounts (with Loans)

With multiple vendors involved when working to make changes to the Core System or test functionality in its entirety prior to rolling out new enhancements, some of our staff are requesting Test Accounts in live.  In regards to this, our teams would like to set up savings, checking accounts, overdraw tolerance, loans, credit cards, external loans, etc in a test account in the live environment.  Has anyone else done this?  If yes, what has been your approach to managing this?  What about approval? How have the examiners felt about your decision? 

Thank you in advance for your inputs.