I was working lately to Virtualize MSCS 2012R2 clusters on vSphere.
According to this kb, it is officially supported on vSphere 5.5 update 1.
I have been spending some time on it and, but for some reason the cluster validation kept failing because of “disk arbitration” test problems.
After contacting all vendors (VMware, HDS, Microsoft) i found out, there is a bug that is related to active-active arrays (in my case VSP) that causes the validation to fail.
If you use any kind of ALUA array, you are bug free, and should be able to implement this.
This bug is handled at the moment by vmware engineering and a fix should be released soon.
UPDATE: this kb popped up , that explains the situation. No solution yet.