VMWare has been capable of that for a long time, although not publicly.
Running OS X under VMware Workstation is not supported by VMware and is not allowed according to apple's EULA. This probably was what you referred towards.
However you can run OS X legally and supported on VMware Fusion and VMware vSphere provided that the hardware it runs on is apple hardware.
Yes I realized that that by itself is probably no good for most of the hackintosh folks, but it is an alternative option if you have a need to run more as one OS X version and want to reduce the cost a bit.
Below is a direct link from the VMware compatility guide on OS X 10.9, you can change the details in the search if you want info about another OS X version.
http://www.vmware.com/resources/compatibility/search.php?dev...