I have been using this: <a href="http://alex.csgraf.de/self/?part/projects&#38;folder/Qemu%20OSX&#38;type/&#38;project/projects&#38;parameters/id=Qemu%20OSX" rel="nofollow">http://alex.csgraf.de/self/?part/projects&#38;folder/Qemu%20...</a> in a triple booted MacBook for some low-level testing on OS X, just to see how it works following the Mac OS X Internals book, the performance is passable, I use virtualization because Apple don't have an ADC Hardware Purchase Program for Brazil and Apple hardware are really expensive here.