Update: The folks at IDC asked that I remove this blog post until further notice.
That said, do check out Roger Johnson's post. He discusses Dell PowerEdge R910 and his Hyper-V deployment at Crutchfield. I met Roger at VMworld 2009. He's a VCP, having run an ESX Server-based datacenter for some time before Crutchfield moved away from VMware and onto Hyper-V/SCVMM earlier this year.
Patrick