For example, one could run "hdparm -E10" to lower the speed of the optical drive. It would be nice to have this feature, if possible at all.
Lowering the speed is useful when watching dvds: When the dvd drives speed is lower it generates only very low amount of noise and vibration on a laptop. Actually on windows, Toshiba provides an app that is called the "acoustic drive silencer" in order to achieve this. I believe its only task is to lower the speed of the drive.
After being so annoyed by the vibration and noise while watching a dvd on my toshiba, I run the above hdparm command and it worked like a charm, no noise at all!
In the future, I hope that gnome power manager in conjunction with totem could use such an infrastructure provided by devicekit-disks to achieve this behaviour automatically.