Here is a new build of Mac on Linux, which was abandoned long long long ago by its original developer. Its a KVM (Kernel Virtual Machine). This video shows Tiger OS X booting as a guest with Lubuntu 12.04 as host.
http://www.youtube.com/watch?v=7alchoY6kzY&feature=youtu.be
It allows OS X PPC to be virtualized on non Apple PowerPC hardware, and in theory I guess if you had say, Lubuntu 12.04 on your Powermac you could virtualize OS X like Paralells and VMware virtualize Windows. But I am not an expert.
http://www.youtube.com/watch?v=7alchoY6kzY&feature=youtu.be
It allows OS X PPC to be virtualized on non Apple PowerPC hardware, and in theory I guess if you had say, Lubuntu 12.04 on your Powermac you could virtualize OS X like Paralells and VMware virtualize Windows. But I am not an expert.