I saw that Microsoft have released the The performance toolkit, I’m not entirely sure what it does but if you want to check it out then get yourself over to pinpoint and get yourself a copy free of charge.
this is a brief summary from the website
The Performance Toolkit is designed to formalize performance testing for Microsoft Dynamics CRM 2011. This Toolkit is highly customizable and can be used by Microsoft Dynamics CRM partners and customers to collect performance data to support decisions related to their CRM 2011 on-premise deployments.
if you want some idea what it does then I saw on Codeplex the CRM 4 version of it, here . I haven’t ever heard of this plugin which is strange because it seems quite popular having been download over 8000 times. Here are some of the key features from Codeplex
1. Multi Organization Performance Testing Support
2. Multi Server Deployment Performance Testing Support
3. Outlook Synchronization and Offline Performance Testing Support
4. Data Management Performance Testing Support
5. Workflow Performance Analysis Support
6. Email Matching Performance Testing Support
7. Ease of deployment of the Toolkit through an MSI package with enhanced configuration of the toolkit.