Yes! I know, when you hear Datacenter Edition you may not think of a solution that fits well in the Small Business space. However, one story in the Windows Server 2008 R2 lineup that is really taking off with Small Business customers is the unlimited Windows Sever VM's in Datacenter Edition.
If you are a small business and you have a need to run multiple instances of Windows Server in a virtualized environment you can buy Windows Server Standard and get the rights to one instance, buy Enterprise and get four, or buy datacenter and get unlimited. Of course, scale and price of the underlying server that is going to run all of those VM's will always be a major factor. With today's server architecture and customers that want to consolidate several simple workloads, Datacenter Edition is becoming a popular choice.
Here’s more info on Windows Server 2008 R2 Datacenter Edition:
Need more info on Licensing Windows in virtual environments? Check this out: