Roush pretty much nailed the approach, low risk all the way.
There appears to be two approaches to sharing LUNs across multiple machines (Caveat: I have not done this, and do not claim to be an expert, but this would be my approach
HyperV with Windows 2008 running CSV:
As with all Microsoft kitchen sink tech, this appears to quote Amadeus, too many notes, all the pieces have to be in place, and you have to identify the machines that are going to be participating.
From the link I provided, you'll see under number four:
CSV allows every cluster node to access the disk concurrently. This is accomplished by creating a common namespace under %SystemDrive%\ClusterStorage. For this reason, it is necessary to have the OS on the same drive letter on every node in the cluster (such as C:\, which will be used in this blog). You will see the same directory from every node in the cluster and this is the way to access CSV disks.
To run CSV you have to be running Server 2008, HyperV, and set up clustering.
VMware running ESXi under Server 2008, using VMFS:
The other approach is the one mentioned earlier in this thread, run ESXi under Windows Server, this will give you VMFS, and NTFS can run on top of that.
In either case you need a Hypervisor to coordinate block access to the disks.
I am VERY interested in your attempts, what you learn, please keep us apprised. I'll help where I can.