Now, that I own an Intel VT capable PC, I'm able to test any kind of automatic Xen VM deployment with SystemImager directly from my laptop, even HVM Xen VMs.
Next step will be to test the deployment of a Xen VM with a Windows raw-disk image, cloned by SystemImager from a VMWare (vmplayer) machine. With this we're finally able to cover all the kind of migrations: virtual-to-virtual (that means migrations between equal or even different virtualization technologies), physical-to-virtual, virtual-to-physical, and physical-to-physical (obviously last one was the main task of SystemImager). And not only with Linux! Anyway, at the moment, this still needs some manual tweaks (read the howtos above) and I would really like to spend some efforts to implement a SystemImager GUI to fully automatize all these steps.