User defined actions (run scripts) with buttons?

[turry]

I and some other persons search
http://plugcomputer.org/plugforum/index.php?topic=973.0
http://plugcomputer.org/plugforum/index.php?topic=1186.0
an option to do things without logged in via terminal. It would be fine to do a shutdown or reset by pushing an button, or maybe to umount an device.

Maybe that can be realized with te GPIO pins?

Does know anybody an solution? (Single key keyboard from shinydevices arent't the right)