I can't think of one, and to be honest I'm not sure why you'd want this.

If you're thinking that not being able to copy/paste anything that's meant to be moderately secure will stop them typing it in a seperate editor I think you're mistaken. People are used to how webbrowsers work, and used to being able to c'n'p into them.. stopping them on your site alone will simply mean they type it into their editor, find they can't c'n'p, so retype it from the 'in editor version' still on screen, and then get irritated at your system for not allowing them to do what they want, and are used to being able to do.

Less secure (Info on screen longer), and less usable than if you'd just obeyed the priniciple of least surprise and let them do what they're trying to.

As to how it'd be done if you had absolutely had to- forget Javascript. If there's a good enough reason that you'd need to disable my browsers basic functionality I have a good enough reason to disable Javascript when I'm using your system.

You'd be better looking at embedded technologies such as Java or Flash, which whilst I appreciate may get eyebrows raised from a lot of Perl-packin' monks does also sidestep the interface familiarity issue.. people aren't as used to being able to c'n'p into an embedded technology anyway.