Sauce does Mac OS X virtualization using some patches Alexander Graf and René Rebe helped them bring up to date, which they've released (see http://sauceio.com/index.php/2012/08/apple-sauce-android-sau...).

I tried hacking their patches into a recent snapshot of the KVM tree but there were some issues. I sort of wonder if anyone else has managed to get their code working, because it would be a neat hack if so.