Nice ideas, Zentho's!
I have created my own computer with 4 working disks and diskdrive. Almost foolproof disk inserting and disk reading design. And a half working e-mail system for two people at a time to use.
I am working on a "friends list" system that allows/dis-allows people e-mailing you, which includes friend invites and blocking. And a password system which allows the user to set a 4 digit password on their unit.
All in the smallest package possible.
If I ever get the chance, I'll post a teaser.