http://www.openvz.org/ http://www.openvz.org/ does what you want. The PID:s, network interfaces, and the like are all isolated, but you are only running one ker

http://www.openvz.org/ http://www.openvz.org/ does what you want. The PID:s, network interfaces, and the like are all isolated, but you are only running one kernel on the whole system. Xen might be work taking a look at as well.