Here is the long and short of this discussion:
Is Mac OS X supported on vSphere 5: Yes
Is Mac OS X supported on vSphere 5 using any x86 based platform: No
Again, Apple threw the EULA book at VMware stating that: While Mac OS X is supported using vSphere 5.0, it is only supported running on Apple hardware (ie. Xserve). Interestingly the Xserve line was discontinued earlier this year. Also just as interesting, VMware has yet to place it on its HCL (Hardware Compatibility List).
May the reader keep in mind… it is not a technical issue of support but rather a political one. Mac OS is based on FreeBSD, which VMware has supported as a virtual machine operating system for many years now. Apple will allow you to virtualize other operating systems on Apple hardware, but not the other way around.
At least Apple is consistent with its stance on creating technology barriers rather than overcoming them.