Regarding "touch screen" navigation, that doesn't mean the entire reading surface need be touchscreen. I think a navigational widget would suffice. I think a thin horizontal band near the bottom of an e-book (new usage of the term, see
this post) could be interesting. You'd turn pages by sliding your finger along the band. Slide faster, turn pages 5 or 10 at a time. Or have "zones" on the band, sliding here turns x many pages, sliding in a different zone turns more or less. User configurable. Combine that with the standard buttons, and you'd have plenty of options for robust navigation.
Please tell your good friend that the whole world waits.