This article initially caught my eye because of the hardware that was used. I found it fairly interesting, here it is for reference. I did some further reading this evening though and noticed that VMware has a whole web page dedicated to virtualizing Exchange.
I wonder how Microsoft will handle products like SQL and Exchange when Hyper-V releases, considering they've always been against virtualizing these in a production environment. They will certainly want too appear confident in its performance, especially when VMware is publishing things like this.
They might need to update their Exchange Support policy for running on virtualization software in the meantime since VMware just made it look a little silly.