Our automation group has a couple of maxed out trash cans just for Mac VMs. The IT department probably can't wait to replace them with the new rackmounts.
As for hacking VMWare I got my hands on a official Mountain Lion image years ago, directly from Apple, which I used to copy/upgrade into new VM each time a new Mac OS was released. I have lying around cca 15 VM's with different flavors of Mac OS each, all tests for various projects for my clients.
As for technically, it's possible. I believe you either have to edit some file or run a patcher to get it to run MacOS though.