Thanks for the comments so far. Please remember to vote for solutions at http://maemo.org/community/brainstor...oaning_device/ and add new solutions for password-protecting certain files or folders, and for ghosting (although the use case described in the Brainstorm idea was really for short term lending of the device, e.g. while in a pub, so ghosting would be a bit tricky and possibly overkill!). If you don't want to add them yourself, I can do it, but I believe you get maemo.org karma if you add them yourself.

To dormant, please note that multiple Linux user profiles and Ubuntu-style Guest Sessions are already listed as possible solutions. Feel free to vote for them.