Recently, I came across this white paper where the Enterprise Strategy Group Lab provided an excellent summary on virtualizing Microsoft SQL Server 2008 R2, Microsoft SharePoint Server 2010 and Microsoft Exchange Server 2010. The white paper covers the technical architecture utilized within the lab, with detailed performance tests and workload scalability graphs. Each section provides an excellent summary and a set of highlights.
I recommend reading this white paper for some insight into the scale that Hyper-V R2 SP1 provides to these applications.
The white paper can be downloaded here.