Running Office SharePoint and SQL Server 2008 in a Hyper-V environment
Because PerformancePoint Server is integrated with SQL Server and Office SharePoint Server (or WSS), I want to mention Dan Wesley's post regarding support and guidance for deploying Office SharePoint Server on Hyper-V in a TechNet article, Using SharePoint Products and Technologies in a Hyper-V virtual environment. It describes a series of tests that were run to measure Office SharePoint Server performance on virtual servers.
SQL Server 2008: There is a good white paper for Hyper-V and SQL Server in Running SQL Server 2008 in a Hyper-V Environment - Best Practices and Performance Recommendations.