Rogue copies of OSX Leopard and Tiger have been running on VMWare for awhile but because most of the drivers are unsupported and not optimized, it is a dog on performance. An Apple blessed and supported version of this would allow a huge leap forward in speed and performance. It would also mark a big change of direction for the company who has always had a zero tollerance policy for Virtualizing OSX.
Apple opened the door for this when they changed the server licensing wording for Leopard from Tiger. From the Leopard Server License:
This License allows you to install and use one copy of the Mac OS X Server software (the "Mac OS X Server Software") on a single Apple-labeled computer. You may also install and use other copies of Mac OS X Server Software on the same Apple-labeled computer, provided that you acquire an individual and valid license from Apple for each of these other copies of Mac OS X Server Software.
Perhaps we’ll see something next week at Macworld?