Dell PowerEdge t710 virtualization suggestions

You really want to consider having an additional DC on bare metal. For your actual hypervisor you might consider running Hyper-V Server 2008r2 or you will have approx 16gb of RAM thats unusable.

Here is what I would be doing:

PowerEdge t710:

Hyper-V Server 2008r2 for the host OS

VM1 - File Server VM2 - Exchange VM3 - Intranet/Sharepoint VM4 - SVN/SQL VM5 - Additional DC

Then I'd buy something relatively low end to be an additional DC, you dont need a lot of horsepower if its just going to be a DC so you could probably get by with about $1500 hardware costs.

Doing it this way you can perform maintenance on either of your DCs and still be able to maintain all your services.