It's very easy. Only we need to put the iPod as disk mode, an then install the OS in the iPod. You can install it, without restart the computer, using the next executable in the Mac Os X DVD : \System\Installation\Packages\OSInstall.mpkg.
The next steep to start from the ipod is restart the computer, pushing alt key to select the start disk. This utilitie will find bootable OS in all the computer units. And the iPod must appear.
I test it with FireWire 400 Mbps and it runs well. You can use it if you want to have different OS versions.