If you are using ppas and backports, the security update situation gets complex anyway. People have been trying to pin down the situation for Gnome Shell packag

If you are using ppas and backports, the security update situation gets complex anyway. People have been trying to pin down the situation for Gnome Shell packages on 12.04, looks like not 5 years because they are 'Universe' packages. The 10.04 server packages, therefore the base, have 5 years of support, so I guess you could simply risk carrying on with 10.04 after the EOL for the desktop? Maybe not for the work machine.