Hi all,
It would always bother me to just unplug my flash drives under linux/knoppix without cleanly unmounting them. Under windows you have the "Safely remove devices" on the taskbar. So I did a bit of searching and if you use the command line:
udisks --detach /dev/sdg
where /dev/sdg is the location of the flash drive, it will be detached and powered down (assuming you haven't still got it mounted.)