I found this via boing-boing while looking for something else: The Kowal Portable Typewriter and Adding Machine, which is the creation of one Mary Robinette Kowal, who is a professional puppeteer and sometime writer.
I wouldn’t want to copy exactly what she did here of course, but this does get me to think. I have an iBook which has been sitting largely idle since I set up my fine dual monitor desktop set-up at home and since I’ve made use of a very sweet 17 inch Powerbook owned by EMU. But this is just the kind of thing that I could/should do to my slightly older but still quite usable G4 iBook to make it a very groovy writing machine.