altcaps, by Protesilaos Stavrou:

The altcaps package helps you apply alternating letter casing to convey sarcasm or mockery. For example, convert this:

I respect the authorities

To this:

i ReSpEcT tHe AuThOrItIeS

The altcaps package thus makes you more effective at textual communication. Plus, you appear sophisticated. tRuSt Me.

@phoe have you tried http://www.splode.com/~friedman/software/emacs-lisp/src/diacriticalize.el