What you describe would not save much power I think. Switch off LCD, spin down disk, reduce CPU to lowest state, power down what peripherals you can -- would at most double your battery life. A suspended laptop can go days before it drains. And suspend-to-RAM works well on most laptops these days. Suspend-to-disk is the problem and it is what tuxonice is about.
On my current machine, suspend-to-RAM is all I need. Though suspend-to-disk (uswsusp, not tuxonice) works too.