I have access to XP win 7 and some versions of 2008 R2,
What I really need to nail is the interaction of the shares between each of these different types of OS, and then the types of programs that people use.
So, basically, if you can run more than 1 VM at a time, and get them to interact via explorer shares (Libraries etc), then that will be a good start.
There is already an open issue (Amongst others) with the Dokan driver and it's use of 64 OS sharing not working as expected. So no rush with those VM's.
So if you can list the sort of applications that you will be (can) use against the Pooled Drive, then that will be good, and the results can go in the testing documentation.
The next step, would be to use them over a share to the pool, and see what happens then.
Different access permissions will need to be done (Dependent on the OS and the availability of domain controllers) (I do not have these setup at home.