Cool that somebody started an article on that. Just by coincidence I also made my experience with Suspend2 tonight. I will add details I discovered soon (NVidia stuff, Sound stuff).
Are you sure about the need of the acpi package? I don't even have it and my system suspends just fine. The powersave package has a dep on acpi, not the hibernate scripts though, AFAIK.
As for the possibility of executing the script as a user: Couldn't the permissions of the hibernate script be changed so that members of the "power" group (seems to exist by default) can execute it.
Anyone tried out Gnome Power Manager already - does it play nice with the hibernate scripts?